PDF

The Portable Document Format (PDF) is a file format developed by Adobe in the 1990s to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems.[2][3] Based on the PostScript language, each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, vector graphics, raster images and other information needed to display it. PDF was standardized as an open format, ISO 32000, in 2008, and no longer requires any royalties for its implementation.[4]

Today, PDF files may contain a variety of content besides flat text and graphics including logical structuring elements, interactive elements such as annotations and form-fields, layers, rich media (including video content) and three dimensional objects using U3D or PRC, and various other data formats. The PDF specification also provides for encryption and digital signatures, file attachments and metadata to enable workflows requiring these features.

Portable Document Format
Adobe PDF
Adobe PDF icon
Filename extension.pdf[note 1]
Internet media type
  • application/pdf,[1]
  • application/x-pdf
  • application/x-bzpdf
  • application/x-gzpdf
Type code'PDF '[1] (including a single space)
Uniform Type Identifier (UTI)com.adobe.pdf
Magic number%PDF
Developed byISO
Initial release15 June 1993
Latest release
2.0
Extended toPDF/A, PDF/E, PDF/UA, PDF/VT, PDF/X
StandardISO 32000-2
Open format?Yes
Websitewww.iso.org/standard/63534.html

History and standardization

Adobe Systems made the PDF specification available free of charge in 1993. In the early years PDF was popular mainly in desktop publishing workflows, and competed with a variety of formats such as DjVu, Envoy, Common Ground Digital Paper, Farallon Replica and even Adobe's own PostScript format.

PDF was a proprietary format controlled by Adobe until it was released as an open standard on July 1, 2008, and published by the International Organization for Standardization as ISO 32000-1:2008,[5][6] at which time control of the specification passed to an ISO Committee of volunteer industry experts. In 2008, Adobe published a Public Patent License to ISO 32000-1 granting royalty-free rights for all patents owned by Adobe that are necessary to make, use, sell, and distribute PDF compliant implementations.[7]

PDF 1.7, the sixth edition of the PDF specification that became ISO 32000-1, includes some proprietary technologies defined only by Adobe, such as Adobe XML Forms Architecture (XFA) and JavaScript extension for Acrobat, which are referenced by ISO 32000-1 as normative and indispensable for the full implementation of the ISO 32000-1 specification. These proprietary technologies are not standardized and their specification is published only on Adobe’s website.[8][9][10][11][12] Many of them are also not supported by popular third-party implementations of PDF.

On July 28, 2017, ISO 32000-2:2017 (PDF 2.0) was published.[13] ISO 32000-2 does not include any proprietary technologies as normative references.[14]

Technical foundations

The PDF combines three technologies:

  • A subset of the PostScript page description programming language, for generating the layout and graphics.
  • A font-embedding/replacement system to allow fonts to travel with the documents.
  • A structured storage system to bundle these elements and any associated content into a single file, with data compression where appropriate.

PostScript

PostScript is a page description language run in an interpreter to generate an image, a process requiring many resources. It can handle graphics and standard features of programming languages such as if and loop commands. PDF is largely based on PostScript but simplified to remove flow control features like these, while graphics commands such as lineto remain.

Often, the PostScript-like PDF code is generated from a source PostScript file. The graphics commands that are output by the PostScript code are collected and tokenized. Any files, graphics, or fonts to which the document refers also are collected. Then, everything is compressed to a single file. Therefore, the entire PostScript world (fonts, layout, measurements) remains intact.

As a document format, PDF has several advantages over PostScript:

  • PDF contains tokenized and interpreted results of the PostScript source code, for direct correspondence between changes to items in the PDF page description and changes to the resulting page appearance.
  • PDF (from version 1.4) supports graphic transparency; PostScript does not.
  • PostScript is an interpreted programming language with an implicit global state, so instructions accompanying the description of one page can affect the appearance of any following page. Therefore, all preceding pages in a PostScript document must be processed to determine the correct appearance of a given page, whereas each page in a PDF document is unaffected by the others. As a result, PDF viewers allow the user to quickly jump to the final pages of a long document, whereas a PostScript viewer needs to process all pages sequentially before being able to display the destination page (unless the optional PostScript Document Structuring Conventions have been carefully complied with).

Technical overview

File structure

A PDF file is a 7-bit ASCII file, except for certain elements that may have binary content. A PDF file starts with a header containing the magic number and the version of the format such as %PDF-1.7. The format is a subset of a COS ("Carousel" Object Structure) format.[15] A COS tree file consists primarily of objects, of which there are eight types:[16]

  • Boolean values, representing true or false
  • Numbers
  • Strings, enclosed within parentheses ((...)), may contain 8-bit characters.
  • Names, starting with a forward slash (/)
  • Arrays, ordered collections of objects enclosed within square brackets ([...])
  • Dictionaries, collections of objects indexed by Names enclosed within double pointy brackets (<<...>>)
  • Streams, usually containing large amounts of data, which can be compressed and binary
  • The null object

Furthermore, there may be comments, introduced with the percent sign (%). Comments may contain 8-bit characters.

Objects may be either direct (embedded in another object) or indirect. Indirect objects are numbered with an object number and a generation number and defined between the obj and endobj keywords. An index table, also called the cross-reference table and marked with the xref keyword, follows the main body and gives the byte offset of each indirect object from the start of the file.[17] This design allows for efficient random access to the objects in the file, and also allows for small changes to be made without rewriting the entire file (incremental update). Beginning with PDF version 1.5, indirect objects may also be located in special streams known as object streams. This technique reduces the size of files that have large numbers of small indirect objects and is especially useful for Tagged PDF.

At the end of a PDF file is a trailer introduced with the trailer keyword. It contains

  • A dictionary
  • An offset to the start of the cross-reference table (the table starting with the xref keyword)
  • And the %%EOF end-of-file marker.

The dictionary contains

  • A reference to the root object of the tree structure, also known as the catalog
  • The count of indirect objects in the cross-reference table
  • And other optional information.

There are two layouts to the PDF files: non-linear (not "optimized") and linear ("optimized"). Non-linear PDF files consume less disk space than their linear counterparts, though they are slower to access because portions of the data required to assemble pages of the document are scattered throughout the PDF file. Linear PDF files (also called "optimized" or "web optimized" PDF files) are constructed in a manner that enables them to be read in a Web browser plugin without waiting for the entire file to download, since they are written to disk in a linear (as in page order) fashion.[18] PDF files may be optimized using Adobe Acrobat software or QPDF.

Imaging model

The basic design of how graphics are represented in PDF is very similar to that of PostScript, except for the use of transparency, which was added in PDF 1.4.

PDF graphics use a device-independent Cartesian coordinate system to describe the surface of a page. A PDF page description can use a matrix to scale, rotate, or skew graphical elements. A key concept in PDF is that of the graphics state, which is a collection of graphical parameters that may be changed, saved, and restored by a page description. PDF has (as of version 1.6) 24 graphics state properties, of which some of the most important are:

Vector graphics

As in PostScript, vector graphics in PDF are constructed with paths. Paths are usually composed of lines and cubic Bézier curves, but can also be constructed from the outlines of text. Unlike PostScript, PDF does not allow a single path to mix text outlines with lines and curves. Paths can be stroked, filled, clipping. Strokes and fills can use any color set in the graphics state, including patterns.

PDF supports several types of patterns. The simplest is the tiling pattern in which a piece of artwork is specified to be drawn repeatedly. This may be a colored tiling pattern, with the colors specified in the pattern object, or an uncolored tiling pattern, which defers color specification to the time the pattern is drawn. Beginning with PDF 1.3 there is also a shading pattern, which draws continuously varying colors. There are seven types of shading pattern of which the simplest are the axial shade (Type 2) and radial shade (Type 3).

Raster images

Raster images in PDF (called Image XObjects) are represented by dictionaries with an associated stream. The dictionary describes properties of the image, and the stream contains the image data. (Less commonly, a raster image may be embedded directly in a page description as an inline image.) Images are typically filtered for compression purposes. Image filters supported in PDF include the general purpose filters

  • ASCII85Decode a filter used to put the stream into 7-bit ASCII
  • ASCIIHexDecode similar to ASCII85Decode but less compact
  • FlateDecode a commonly used filter based on the deflate algorithm defined in RFC 1951 (deflate is also used in the gzip, PNG, and zip file formats among others); introduced in PDF 1.2; it can use one of two groups of predictor functions for more compact zlib/deflate compression: Predictor 2 from the TIFF 6.0 specification and predictors (filters) from the PNG specification (RFC 2083)
  • LZWDecode a filter based on LZW Compression; it can use one of two groups of predictor functions for more compact LZW compression: Predictor 2 from the TIFF 6.0 specification and predictors (filters) from the PNG specification
  • RunLengthDecode a simple compression method for streams with repetitive data using the run-length encoding algorithm and the image-specific filters
  • DCTDecode a lossy filter based on the JPEG standard
  • CCITTFaxDecode a lossless bi-level (black/white) filter based on the Group 3 or Group 4 CCITT (ITU-T) fax compression standard defined in ITU-T T.4 and T.6
  • JBIG2Decode a lossy or lossless bi-level (black/white) filter based on the JBIG2 standard, introduced in PDF 1.4
  • JPXDecode a lossy or lossless filter based on the JPEG 2000 standard, introduced in PDF 1.5

Normally all image content in a PDF is embedded in the file. But PDF allows image data to be stored in external files by the use of external streams or Alternate Images. Standardized subsets of PDF, including PDF/A and PDF/X, prohibit these features.

Text

Text in PDF is represented by text elements in page content streams. A text element specifies that characters should be drawn at certain positions. The characters are specified using the encoding of a selected font resource.

A font object in PDF is a description of a digital typeface. It may either describe the characteristics of a typeface, or it may include an embedded font file. The latter case is called an embedded font while the former is called an unembedded font. The font files that may be embedded are based on widely used standard digital font formats: Type 1 (and its compressed variant CFF), TrueType, and (beginning with PDF 1.6) OpenType. Additionally PDF supports the Type 3 variant in which the components of the font are described by PDF graphic operators.

Fourteen typefaces, known as the standard 14 fonts, have a special significance in PDF documents:

These fonts are sometimes called the base fourteen fonts.[19] These fonts, or suitable substitute fonts with the same metrics, should be available in most PDF readers, but they are not guaranteed to be available in the reader, and may only display correctly if the system has them installed.[20] Fonts may be substituted if they are not embedded in a PDF.

Within text strings, characters are shown using character codes (integers) that map to glyphs in the current font using an encoding. There are a number of predefined encodings, including WinAnsi, MacRoman, and a large number of encodings for East Asian languages, and a font can have its own built-in encoding. (Although the WinAnsi and MacRoman encodings are derived from the historical properties of the Windows and Macintosh operating systems, fonts using these encodings work equally well on any platform.) PDF can specify a predefined encoding to use, the font's built-in encoding or provide a lookup table of differences to a predefined or built-in encoding (not recommended with TrueType fonts).[21] The encoding mechanisms in PDF were designed for Type 1 fonts, and the rules for applying them to TrueType fonts are complex.

For large fonts or fonts with non-standard glyphs, the special encodings Identity-H (for horizontal writing) and Identity-V (for vertical) are used. With such fonts it is necessary to provide a ToUnicode table if semantic information about the characters is to be preserved.

Transparency

The original imaging model of PDF was, like PostScript's, opaque: each object drawn on the page completely replaced anything previously marked in the same location. In PDF 1.4 the imaging model was extended to allow transparency. When transparency is used, new objects interact with previously marked objects to produce blending effects. The addition of transparency to PDF was done by means of new extensions that were designed to be ignored in products written to the PDF 1.3 and earlier specifications. As a result, files that use a small amount of transparency might view acceptably in older viewers, but files making extensive use of transparency could be viewed incorrectly in an older viewer without warning.

The transparency extensions are based on the key concepts of transparency groups, blending modes, shape, and alpha. The model is closely aligned with the features of Adobe Illustrator version 9. The blend modes were based on those used by Adobe Photoshop at the time. When the PDF 1.4 specification was published, the formulas for calculating blend modes were kept secret by Adobe. They have since been published.[22]

The concept of a transparency group in PDF specification is independent of existing notions of "group" or "layer" in applications such as Adobe Illustrator. Those groupings reflect logical relationships among objects that are meaningful when editing those objects, but they are not part of the imaging model.

Interactive elements

PDF files may contain interactive elements such as annotations, form fields, video, 3D and rich media.

Rich Media PDF is a PDF file including interactive content that can be embedded or linked within the file.

Interactive Forms is a mechanism to add forms to the PDF file format.

PDF currently supports two different methods for integrating data and PDF forms. Both formats today coexist in PDF specification:[23][24][25][26]

  • AcroForms (also known as Acrobat forms), introduced in the PDF 1.2 format specification and included in all later PDF specifications.
  • Adobe XML Forms Architecture (XFA) forms, introduced in the PDF 1.5 format specification. Adobe XFA Forms are not compatible with AcroForms.[27] XFA was deprecated from PDF with PDF 2.0.

AcroForms

AcroForms were introduced in the PDF 1.2 format. AcroForms permit using objects (e.g. text boxes, Radio buttons, etc.) and some code (e.g. JavaScript).

Alongside the standard PDF action types, interactive forms (AcroForms) support submitting, resetting, and importing data. The "submit" action transmits the names and values of selected interactive form fields to a specified uniform resource locator (URL). Interactive form field names and values may be submitted in any of the following formats, (depending on the settings of the action’s ExportFormat, SubmitPDF, and XFDF flags):[23]

  • HTML Form format (HTML 4.01 Specification since PDF 1.5; HTML 2.0 since 1.2)
  • Forms Data Format (FDF)
  • XML Forms Data Format (XFDF) (external XML Forms Data Format Specification, Version 2.0; supported since PDF 1.5; it replaced the "XML" form submission format defined in PDF 1.4)
  • PDF (the entire document can be submitted rather than individual fields and values). (defined in PDF 1.4)

AcroForms can keep form field values in external stand-alone files containing key:value pairs. The external files may use Forms Data Format (FDF) and XML Forms Data Format (XFDF) files.[28][29][30] The usage rights (UR) signatures define rights for import form data files in FDF, XFDF and text (CSV/TSV) formats, and export form data files in FDF and XFDF formats.[23]

Forms Data Format (FDF)
Filename extension.fdf
Internet media typeapplication/vnd.fdf[31]
Type code'FDF'
Developed byAdobe Systems
Initial release1996 (PDF 1.2)
Extended fromPDF
Extended toXFDF
StandardISO 32000-2:2017
Open format?Yes

The Forms Data Format (FDF) is based on PDF, it uses the same syntax and has essentially the same file structure, but is much simpler than PDF, since the body of an FDF document consists of only one required object. Forms Data Format is defined in the PDF specification (since PDF 1.2). The Forms Data Format can be used when submitting form data to a server, receiving the response, and incorporating into the interactive form. It can also be used to export form data to stand-alone files that can be imported back into the corresponding PDF interactive form.

XML Forms Data Format (XFDF)
Filename extension.xfdf
Internet media typeapplication/vnd.adobe.xfdf[32]
Type code'XFDF'
Developed byAdobe Systems
Initial releaseJuly 2003 (referenced in PDF 1.5)
Latest release
3.0
(August 2009)
Extended fromPDF, FDF, XML
StandardISO 19444-1[33])
WebsiteXFDF 3.0 specification

XML Forms Data Format (XFDF) is the XML version of Forms Data Format, but the XFDF implements only a subset of FDF containing forms and annotations. There are not XFDF equivalents for some entries in the FDF dictionary – such as the Status, Encoding, JavaScript, Pages keys, EmbeddedFDFs, Differences and Target. In addition, XFDF does not allow the spawning, or addition, of new pages based on the given data; as can be done when using an FDF file. The XFDF specification is referenced (but not included) in PDF 1.5 specification (and in later versions). It is described separately in XML Forms Data Format Specification.[29] The PDF 1.4 specification allowed form submissions in XML format, but this was replaced by submissions in XFDF format in the PDF 1.5 specification. XFDF conforms to the XML standard.

As of December 2016, XFDF 3.0 is an ISO/IEC standard under the formal name ISO 19444-1:2016 – Document management – XML Forms Data Format – Part 1: Use of ISO 32000-2 (XFDF 3.0).[34] This standard is a normative reference of ISO 32000-2.

XFDF can be used in the same way as FDF; e.g., form data is submitted to a server, modifications are made, then sent back and the new form data is imported in an interactive form. It can also be used to export form data to stand-alone files that can be imported back into the corresponding PDF interactive form.

Adobe XML Forms Architecture (XFA)

In PDF 1.5, Adobe Systems introduced a proprietary format for forms; Adobe XML Forms Architecture (XFA). Adobe XFA Forms are not compatible with ISO 32000's AcroForms feature, and most PDF processors do not handle XFA content. The XFA specification is referenced from ISO 32000-1 / PDF 1.7 as an external proprietary specification, and was entirely deprecated from PDF with ISO 32000-2 (PDF 2.0).

Logical structure and accessibility

A "tagged" PDF (see clause 14.8 in ISO 32000) includes document structure and semantics information to enable reliable text extraction and accessibility. Technically speaking, tagged PDF is a stylized use of the format that builds on the logical structure framework introduced in PDF 1.3. Tagged PDF defines a set of standard structure types and attributes that allow page content (text, graphics, and images) to be extracted and reused for other purposes.[35]

Tagged PDF is not required in situations where a PDF file is intended only for print. Since the feature is optional, and since the rules for Tagged PDF were relatively vague in ISO 32000-1, support for tagged PDF amongst consuming devices, including assistive technology (AT), is uneven at this time.[36] ISO 32000-2, however, includes an improved discussion of tagged PDF which is anticipated to facilitate

An ISO-standardized subset of PDF specifically targeted at accessibility; PDF/UA, was first published in 2012.

Optional Content Groups (layers of it)

With the introduction of PDF version, 1.5 (2003) came the concept of Layers. Layers, or as they are more formally known Optional Content Groups (OCGs), refer to sections of content in a PDF document that can be selectively viewed or hidden by document authors or consumers. This capability is useful in CAD drawings, layered artwork, maps, multi-language documents etc. Basically, it consists of an Optional Content Properties Dictionary added to the document root. This dictionary contains an array of Optional Content Groups (OCGs), each describing a set of information and each of which may be individually displayed or suppressed, plus a set of Optional Content Configuration Dictionaries, which give the status (Displayed or Suppressed) of the given OCGs.

Security and signatures

A PDF file may be encrypted for security, or digitally signed for authentication. However, since a SHA-1 collision was discovered making use of the PDF format, digital signatures using SHA-1 have been shown to be insecure.[37]

The standard security provided by Acrobat PDF consists of two different methods and two different passwords: a user password, which encrypts the file and prevents opening, and an owner password, which specifies operations that should be restricted even when the document is decrypted, which can include modifying, printing, or copying text and graphics out of the document, or adding or modifying text notes and AcroForm fields. The user password encrypts the file, while the owner password does not, instead relying on client software to respect these restrictions. An owner password can easily be removed by software, including some free online services.[38] Thus, the use restrictions that a document author places on a PDF document are not secure, and cannot be assured once the file is distributed; this warning is displayed when applying such restrictions using Adobe Acrobat software to create or edit PDF files.

Even without removing the password, most freeware or open source PDF readers ignore the permission "protections" and allow the user to print or make copy of excerpts of the text as if the document were not limited by password protection.[39][40][41]

There are a number of commercial solutions that offer more robust means of information rights management. Not only can they restrict document access but they also reliably enforce permissions in ways that the standard security handler does not.[42]

Usage rights

Beginning with PDF 1.5, Usage rights (UR) signatures are used to enable additional interactive features that are not available by default in a particular PDF viewer application. The signature is used to validate that the permissions have been granted by a bona fide granting authority. For example, it can be used to allow a user:[23]

  • To save the PDF document along with modified form and/or annotation data
  • Import form data files in FDF, XFDF, and text (CSV/TSV) formats
  • Export form data files in FDF and XFDF formats
  • Submit form data
  • Instantiate new pages from named page templates
  • Apply a digital signature to existing digital signature form field
  • Create, delete, modify, copy, import, and export annotations

For example, Adobe Systems grants permissions to enable additional features in Adobe Reader, using public-key cryptography. Adobe Reader verifies that the signature uses a certificate from an Adobe-authorized certificate authority. Any PDF application can use this same mechanism for its own purposes.[23]

File attachments

PDF files can have file attachments which processors may access and open or save to a local filesystem.

Metadata

PDF files can contain two types of metadata.[43] The first is the Document Information Dictionary, a set of key/value fields such as author, title, subject, creation and update dates. This is stored in the optional Info trailer of the file. A small set of fields is defined, and can be extended with additional text values if required. This method is deprecated in PDF 2.0.

In PDF 1.4, support was added for Metadata Streams, using the Extensible Metadata Platform (XMP) to add XML standards-based extensible metadata as used in other file formats. This allows metadata to be attached to any stream in the document, such as information about embedded illustrations, as well as the whole document (attaching to the document catalog), using an extensible schema.

Usage restrictions and monitoring

PDFs may be encrypted so that a password is needed to view or edit the contents. PDF 2.0 defines 256-bit AES encryption as standard for PDF 2.0 files. The PDF Reference also defines ways that third parties can define their own encryption systems for PDF.

PDF files may be digitally signed; complete details on implementing digital signatures in PDF is provided in ISO 32000-2.

PDF files may also contain embedded DRM restrictions that provide further controls that limit copying, editing or printing. These restrictions depend on the reader software to obey them, so the security they provide is limited.

Default display settings

PDF documents can contain display settings, including the page display layout and zoom level. Adobe Reader uses these settings to override the user's default settings when opening the document.[44] The free Adobe Reader cannot remove these settings.

Intellectual property

Anyone may create applications that can read and write PDF files without having to pay royalties to Adobe Systems; Adobe holds patents to PDF, but licenses them for royalty-free use in developing software complying with its PDF specification.[45]

Technical issues

Accessibility

PDF files can be created specifically to be accessible for disabled people.[46][47][48][49][50] PDF file formats in use as of 2014 can include tags, text equivalents, captions, audio descriptions, and more. Some software can automatically produce tagged PDFs, but this feature is not always enabled by default.[51][52] Leading screen readers, including JAWS, Window-Eyes, Hal, and Kurzweil 1000 and 3000 can read tagged PDF.[53][54] Moreover, tagged PDFs can be re-flowed and magnified for readers with visual impairments. Adding tags to older PDFs and those that are generated from scanned documents can present some challenges.

One of the significant challenges with PDF accessibility is that PDF documents have three distinct views, which, depending on the document's creation, can be inconsistent with each other. The three views are (i) the physical view, (ii) the tags view, and (iii) the content view. The physical view is displayed and printed (what most people consider a PDF document). The tags view is what screen readers and other assistive technologies use to deliver a high-quality navigation and reading experience to users with disabilities. The content view is based on the physical order of objects within the PDF's content stream and may be displayed by software that does not fully support the tags view, such as the Reflow feature in Adobe's Reader.

PDF/UA, the International Standard for accessible PDF based on ISO 32000-1 was first published as ISO 14289-1 in 2012, and establishes normative language for accessible PDF technology.

Viruses and exploits

PDF attachments carrying viruses were first discovered in 2001. The virus, named OUTLOOK.PDFWorm or Peachy, uses Microsoft Outlook to send itself as an attachment to an Adobe PDF file. It was activated with Adobe Acrobat, but not with Acrobat Reader.[55]

From time to time, new vulnerabilities are discovered in various versions of Adobe Reader,[56] prompting the company to issue security fixes. Other PDF readers are also susceptible. One aggravating factor is that a PDF reader can be configured to start automatically if a web page has an embedded PDF file, providing a vector for attack. If a malicious web page contains an infected PDF file that takes advantage of a vulnerability in the PDF reader, the system may be compromised even if the browser is secure. Some of these vulnerabilities are a result of the PDF standard allowing PDF documents to be scripted with JavaScript. Disabling JavaScript execution in the PDF reader can help mitigate such future exploits, although it does not protect against exploits in other parts of the PDF viewing software. Security experts say that JavaScript is not essential for a PDF reader, and that the security benefit that comes from disabling JavaScript outweighs any compatibility issues caused.[57] One way of avoiding PDF file exploits is to have a local or web service convert files to another format before viewing.

On March 30, 2010 security researcher Didier Stevens reported an Adobe Reader and Foxit Reader exploit that runs a malicious executable if the user allows it to launch when asked.[58]

Content

A PDF file is often a combination of vector graphics, text, and bitmap graphics. The basic types of content in a PDF are:

  • Text stored as content streams (i.e., not encoded in plain text)
  • Vector graphics for illustrations and designs that consist of shapes and lines
  • Raster graphics for photographs and other types of image
  • Multimedia objects in the document

In later PDF revisions, a PDF document can also support links (inside document or web page), forms, JavaScript (initially available as plugin for Acrobat 3.0), or any other types of embedded contents that can be handled using plug-ins.

PDF 1.6 supports interactive 3D documents embedded in the PDF – 3D drawings can be embedded using U3D or PRC and various other data formats.[59][60]

Two PDF files that look similar on a computer screen may be of very different sizes. For example, a high resolution raster image takes more space than a low resolution one. Typically higher resolution is needed for printing documents than for displaying them on screen. Other things that may increase the size of a file is embedding full fonts, especially for Asiatic scripts, and storing text as graphics.

Software

PDF viewers are generally provided free of charge, and many versions are available from a variety of sources.

There are many software options for creating PDFs, including the PDF printing capabilities built into macOS, iOS,[61] and most Linux distributions, LibreOffice, Microsoft Office 2007 (if updated to SP2) and later,[62] WordPerfect 9, Scribus, numerous PDF print drivers for Microsoft Windows, the pdfTeX typesetting system, the DocBook PDF tools, applications developed around Ghostscript and Adobe Acrobat itself as well as Adobe InDesign, Adobe FrameMaker, Adobe Illustrator, Adobe Photoshop. Google's online office suite Google Docs also allows for uploading and saving to PDF.

Raster image processors (RIPs) are used to convert PDF files into a raster format suitable for imaging onto paper and other media in printers, digital production presses and prepress in a process known as rasterisation. RIPs capable of processing PDF directly include the Adobe PDF Print Engine[63] from Adobe Systems and Jaws[64] and the Harlequin RIP from Global Graphics.

Conversions

Documents saved in PDF (Portable Document Format, Portable Document Format for Archiving, Forms Data Format, any printable document) could be converted back and forth from many other formats such as[65]:

  • Microsoft Office formats,
  • Rich Text Format,
  • Open office,
  • WordPerfect,
  • Microsoft Windows Bitmap,
  • Windows Metafile,
  • Enhanced Metafile,
  • Graphics Interchange Format,
  • Microsoft HD Photo File,
  • JPEG File Interchange,
  • JPEG 2000 File Format and Code Stream,
  • Portable Network Graphics,
  • Tagged Image File,
  • HyperText Markup Language,
  • MIME Encapsulation of Aggregate HTML Documents,
  • Scalable Vector Graphics,
  • Microsoft Outlook, Text,
  • XML Paper Specification,
  • Extensible Markup Language,
  • Silverlight XPS Document,
  • Extensible Application Markup Language

etc.

Companies such as Adobe Acrobat provide SDK libraries for developers to add and create PDF features in any software. Besides Adobe PDF Library, companies such as PDFTron Systems, Apache PDFBox, and Foxit Software provide similar SDKs.

Annotation

Adobe Acrobat is one example of proprietary software that allows the user to annotate, highlight, and add notes to already created PDF files. One UNIX application available as free software (under the GNU General Public License) is PDFedit. The freeware Foxit Reader, available for Microsoft Windows, macOS and Linux, allows annotating documents. Tracker Software's PDF-XChange Viewer allows annotations and markups without restrictions in its freeware alternative. Apple's macOS's integrated PDF viewer, Preview, does also enable annotations as does the open source software Skim, with the latter supporting interaction with LaTeX, SyncTeX, and PDFSync and integration with BibDesk reference management software. Freeware Qiqqa can create an annotation report that summarizes all the annotations and notes one has made across their library of PDFs.

There are also web annotation systems that support annotation in pdf and other documents formats. In cases where PDFs are expected to have all of the functionality of paper documents, ink annotation is required.

Other

Examples of PDF software as online services including Scribd for viewing and storing, Pdfvue for online editing, and Thinkfree, Zamzar for conversion.

In 1993 the Jaws raster image processor from Global Graphics became the first shipping prepress RIP that interpreted PDF natively without conversion to another format. The company released an upgrade to their Harlequin RIP with the same capability in 1997.[66]

Agfa-Gevaert introduced and shipped Apogee, the first prepress workflow system based on PDF, in 1997.

Many commercial offset printers have accepted the submission of press-ready PDF files as a print source, specifically the PDF/X-1a subset and variations of the same.[67] The submission of press-ready PDF files are a replacement for the problematic need for receiving collected native working files.

PDF was selected as the "native" metafile format for Mac OS X, replacing the PICT format of the earlier classic Mac OS. The imaging model of the Quartz graphics layer is based on the model common to Display PostScript and PDF, leading to the nickname Display PDF. The Preview application can display PDF files, as can version 2.0 and later of the Safari web browser. System-level support for PDF allows Mac OS X applications to create PDF documents automatically, provided they support the OS-standard printing architecture. The files are then exported in PDF 1.3 format according to the file header. When taking a screenshot under Mac OS X versions 10.0 through 10.3, the image was also captured as a PDF; later versions save screen captures as a PNG file, though this behaviour can be set back to PDF if desired.

In 2006 PDF was widely accepted as the standard print job format at the Open Source Development Labs Printing Summit. It is supported as a print job format by the Common Unix Printing System and desktop application projects such as GNOME, KDE, Firefox, Thunderbird, LibreOffice and OpenOffice have switched to emit print jobs in PDF.[68]

Some desktop printers also support direct PDF printing, which can interpret PDF data without external help. Currently, all PDF capable printers also support PostScript, but most PostScript printers do not support direct PDF printing.

The Free Software Foundation once thought of as one of their high priority projects to be "developing a free, high-quality and fully functional set of libraries and programs that implement the PDF file format and associated technologies to the ISO 32000 standard."[69][70] In 2011, however, the GNU PDF project was removed from the list of "high priority projects" due to the maturation of the Poppler library,[71] which has enjoyed wider use in applications such as Evince with the GNOME desktop environment. Poppler is based on Xpdf[72][73] code base. There are also commercial development libraries available as listed in List of PDF software.

The Apache PDFBox project of the Apache Software Foundation is an open source Java library for working with PDF documents. PDFBox is licensed under the Apache License.[74]

See also

Notes

  1. ^ Before Adobe Acrobat and Portable Document Format, file extension .pdf was used by a word processor named WordStar, which used this extension for printer definition files.

References

  1. ^ a b The application/pdf Media Type, 2004, RFC 3778
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  74. ^ The Apache PDFBox project . Retrieved 2009-09-19.

Further reading

External links

2018 FIFA World Cup

The 2018 FIFA World Cup was the 21st FIFA World Cup, an international football tournament contested by the men's national teams of the member associations of FIFA once every four years. It took place in Russia from 14 June to 15 July 2018. It was the first World Cup to be held in Eastern Europe, and the 11th time that it had been held in Europe. At an estimated cost of over $14.2 billion, it was the most expensive World Cup. It was also the first World Cup to use the video assistant referee (VAR) system.The finals involved 32 teams, of which 31 came through qualifying competitions, while the host nation qualified automatically. Of the 32 teams, 20 had also appeared in the previous tournament in 2014, while both Iceland and Panama made their first appearances at a FIFA World Cup. A total of 64 matches were played in 12 venues across 11 cities.Germany were the defending champions, but were eliminated in the group stage.

The final took place on 15 July at the Luzhniki Stadium in Moscow, between France and Croatia. France won the match 4–2 to claim their second World Cup title, marking the fourth consecutive title won by a European team.

Baseball

Baseball is a bat-and-ball game played between two opposing teams who take turns batting and fielding. The game proceeds when a player on the fielding team, called the pitcher, throws a ball which a player on the batting team tries to hit with a bat. The objectives of the offensive team (batting team) are to hit the ball into the field of play, and to run the bases—having its runners advance counter-clockwise around four bases to score what are called "runs". The objective of the defensive team (fielding team) is to prevent batters from becoming runners, and to prevent runners' advance around the bases. A run is scored when a runner legally advances around the bases in order and touches home plate (the place where the player started as a batter). The team that scores the most runs by the end of the game is the winner.

The first objective of the batting team is to have a player reach first base safely. A player on the batting team who reaches first base without being called "out" can attempt to advance to subsequent bases as a runner, either immediately or during teammates' turns batting. The fielding team tries to prevent runs by getting batters or runners "out", which forces them out of the field of play. Both the pitcher and fielders have methods of getting the batting team's players out. The opposing teams switch back and forth between batting and fielding; the batting team's turn to bat is over once the fielding team records three outs. One turn batting for each team constitutes an inning. A game is usually composed of nine innings, and the team with the greater number of runs at the end of the game wins. If scores are tied at the end of nine innings, extra innings are usually played. Baseball has no game clock, although most games end in the ninth inning.

Baseball evolved from older bat-and-ball games already being played in England by the mid-18th century. This game was brought by immigrants to North America, where the modern version developed. By the late 19th century, baseball was widely recognized as the national sport of the United States. Baseball is popular in North America and parts of Central and South America, the Caribbean, and East Asia, particularly in Japan and South Korea.

In the United States and Canada, professional Major League Baseball (MLB) teams are divided into the National League (NL) and American League (AL), each with three divisions: East, West, and Central. The MLB champion is determined by playoffs that culminate in the World Series. The top level of play is similarly split in Japan between the Central and Pacific Leagues and in Cuba between the West League and East League. The World Baseball Classic, organized by the World Baseball Softball Confederation, is the major international competition of the sport and attracts the top national teams from around the world.

Colombia

Colombia ( (listen) kə-LUM-bee-ə, -⁠LOM-; Spanish: [koˈlombja] (listen)), officially the Republic of Colombia (Spanish: República de Colombia ), is a sovereign state largely situated in the northwest of South America, with territories in Central America. Colombia shares a border to the northwest with Panama, to the east with Venezuela and Brazil and to the south with Ecuador and Peru. It shares its maritime limits with Costa Rica, Nicaragua, Honduras, Jamaica, Haiti, and the Dominican Republic. Colombia is a unitary, constitutional republic comprising thirty-two departments, with the capital in Bogota.

Colombia has been inhabited by various indigenous peoples since 12,000 BCE, including the Muisca, Quimbaya, and the Tairona. The Spanish arrived in 1499 and by the mid-16th century conquered and colonized much of the region, establishing the New Kingdom of Granada, with Santafé de Bogotá as its capital. Independence from Spain was achieved in 1819, but by 1830 the "Gran Colombia" Federation was dissolved, with what is now Colombia and Panama emerging as the Republic of New Granada. The new nation experimented with federalism as the Granadine Confederation (1858), and then the United States of Colombia (1863), before the Republic of Colombia was finally declared in 1886. Panama seceded in 1903, leading to Colombia's present borders. Beginning in the 1960s, the country suffered from an asymmetric low-intensity armed conflict and rampant political violence, both of which escalated in the 1990s. Since 2005, there has been significant improvement in security, stability, and rule of law.Colombia is one of the most ethnically and linguistically diverse countries in the world, with its rich cultural heritage reflecting influences by indigenous peoples, European settlement, forced African migration, immigration from Europe and the Middle East. Urban centres are mostly located in the highlands of the Andes mountains and the Caribbean coast.

Colombia is among the world's 17 megadiverse countries, and the most densely biodiverse per square kilometer; its territory encompasses Amazon rainforest, tropical grassland and coastlines along both the Caribbean and Pacific.

Colombia is a middle power and regional actor in Latin America. It is part of the CIVETS group of six leading emerging markets and a member of the UN, the WTO, the OAS, the Pacific Alliance, and other international organizations. Colombia's diversified economy is the fourth largest in Latin America, with macroeconomic stability and favorable long-term growth prospects.

Germany

Germany (German: Deutschland German pronunciation: [ˈdɔʏtʃlant]), officially the Federal Republic of Germany (German: Bundesrepublik Deutschland, listen ), is a country in Central and Western Europe, lying between the Baltic and North Seas to the north, and the Alps to the south. It borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, France to the southwest, and Luxembourg, Belgium and the Netherlands to the west.

Germany includes 16 constituent states, covers an area of 357,386 square kilometres (137,988 sq mi), and has a largely temperate seasonal climate. With 83 million inhabitants, it is the second most populous state of Europe after Russia, the most populous state lying entirely in Europe, as well as the most populous member state of the European Union. Germany is a very decentralized country. Its capital and largest metropolis is Berlin, while Frankfurt serves as its financial capital and has the country's busiest airport. Germany's largest urban area is the Ruhr, with its main centres of Dortmund and Essen. The country's other major cities are Hamburg, Munich, Cologne, Stuttgart, Düsseldorf, Leipzig, Dresden, Bremen, Hannover, and Nuremberg.

Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before 100 AD. During the Migration Period, the Germanic tribes expanded southward. Beginning in the 10th century, German territories formed a central part of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation. After the collapse of the Holy Roman Empire, the German Confederation was formed in 1815. The German revolutions of 1848–49 resulted in the Frankfurt Parliament establishing major democratic rights.

In 1871, Germany became a nation state when most of the German states (most notably excluding Switzerland and Austria) unified into the Prussian-dominated German Empire. After World War I and the revolution of 1918–19, the Empire was replaced by the parliamentary Weimar Republic. The Nazi seizure of power in 1933 led to the establishment of a dictatorship, the annexation of Austria, World War II, and the Holocaust. After the end of World War II in Europe and a period of Allied occupation, Austria was re-established as an independent country and two new German states were founded: West Germany, formed from the American, British, and French occupation zones, and East Germany, formed from the Soviet occupation zone. Following the Revolutions of 1989 that ended communist rule in Central and Eastern Europe, the country was reunified on 3 October 1990.Today, the sovereign state of Germany is a federal parliamentary republic led by a chancellor. It is a great power with a strong economy; it has the world's fourth-largest economy by nominal GDP, and the fifth-largest by PPP. As a global leader in several industrial and technological sectors, it is both the world's third-largest exporter and importer of goods. As a developed country with a very high standard of living, it upholds a social security and universal health care system, environmental protection, and a tuition-free university education.

The Federal Republic of Germany was a founding member of the European Economic Community in 1957 and the European Union in 1993. It is part of the Schengen Area and became a co-founder of the Eurozone in 1999. Germany is a member of the United Nations, NATO, the G7, the G20, and the OECD. Known for its rich cultural history, Germany has been continuously the home of influential and successful artists, philosophers, musicians, film people, sportspeople, entrepreneurs, scientists, engineers, and inventors. Germany has a large number of World Heritage sites and is among the top tourism destinations in the world.

Global warming

Global warming is a long-term rise in the average temperature of the Earth's climate system, an aspect of climate change shown by temperature measurements and by multiple effects of the warming. The term commonly refers to the mainly human-caused observed warming since pre-industrial times and its projected continuation, though there were also much earlier periods of global warming. In the modern context the terms global warming and climate change are commonly used interchangeably, but climate change includes both global warming and its effects, such as changes to precipitation and impacts that differ by region. Many of the observed warming changes since the 1950s are unprecedented in the instrumental temperature record, and in historical and paleoclimate proxy records of climate change over thousands to millions of years.In 2013, the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report concluded, "It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century." The largest human influence has been the emission of greenhouse gases such as carbon dioxide, methane, and nitrous oxide. Climate model projections summarized in the report indicated that during the 21st century, the global surface temperature is likely to rise a further 0.3 to 1.7 °C (0.5 to 3.1 °F) to 2.6 to 4.8 °C (4.7 to 8.6 °F) depending on the rate of greenhouse gas emissions and on climate feedback effects. These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing.Future climate change effects are expected to include rising sea levels, ocean acidification, regional changes in precipitation, and expansion of deserts in the subtropics. Surface temperature increases are greatest in the Arctic, with the continuing retreat of glaciers, permafrost, and sea ice. Predicted regional precipitation effects include more frequent extreme weather events such as heat waves, droughts, wildfires, heavy rainfall with floods, and heavy snowfall. Effects directly significant to humans are predicted to include the threat to food security from decreasing crop yields, and the abandonment of populated areas due to rising sea levels. Environmental impacts appear likely to include the extinction or relocation of ecosystems as they adapt to climate change, with coral reefs, mountain ecosystems, and Arctic ecosystems most immediately threatened. Because the climate system has a large "inertia" and greenhouse gases will remain in the atmosphere for a long time, climatic changes and their effects will continue to become more pronounced for many centuries even if further increases to greenhouse gases stop.Possible societal responses to global warming include mitigation by emissions reduction, adaptation to its effects, and possible future climate engineering. Most countries are parties to the United Nations Framework Convention on Climate Change (UNFCCC), whose ultimate objective is to prevent dangerous anthropogenic climate change. Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 °C (3.6 °F) compared to pre-industrial levels, with efforts made to limit warming to 1.5 °C (2.7 °F). Some scientists call into question climate adaptation feasibility, with higher emissions scenarios, or the two degree temperature target.Public reactions to global warming and concern about its effects are also increasing. A global 2015 Pew Research Center report showed that a median of 54% of all respondents asked consider it "a very serious problem". Significant regional differences exist, with Americans and Chinese (whose economies are responsible for the greatest annual CO2 emissions) among the least concerned.

HIV/AIDS

Human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV). Following initial infection, a person may not notice any symptoms or may experience a brief period of influenza-like illness. Typically, this is followed by a prolonged period with no symptoms. As the infection progresses, it interferes more with the immune system, increasing the risk of developing common infections such as tuberculosis, as well as other opportunistic infections, and tumors that rarely affect people who have uncompromised immune systems. These late symptoms of infection are referred to as acquired immunodeficiency syndrome (AIDS). This stage is often also associated with unintended weight loss.HIV is spread primarily by unprotected sex (including anal and oral sex), contaminated blood transfusions, hypodermic needles, and from mother to child during pregnancy, delivery, or breastfeeding. Some bodily fluids, such as saliva and tears, do not transmit HIV. Methods of prevention include safe sex, needle exchange programs, treating those who are infected, pre- and post-exposure prophylaxis, and male circumcision. Disease in a baby can often be prevented by giving both the mother and child antiretroviral medication. There is no cure or vaccine; however, antiretroviral treatment can slow the course of the disease and may lead to a near-normal life expectancy. Treatment is recommended as soon as the diagnosis is made. Without treatment, the average survival time after infection is 11 years.In 2016, about 36.7 million people were living with HIV and it resulted in 1 million deaths. There were 300,000 fewer new HIV cases in 2016 than in 2015. Most of those infected live in sub-Saharan Africa. From the time AIDS was identified in the early 1980s to 2017, the disease has caused an estimated 35 million deaths worldwide. HIV/AIDS is considered a pandemic—a disease outbreak which is present over a large area and is actively spreading. HIV originated in west-central Africa during the late 19th or early 20th century. AIDS was first recognized by the United States Centers for Disease Control and Prevention (CDC) in 1981 and its cause—HIV infection—was identified in the early part of the decade.HIV/AIDS has had a large impact on society, both as an illness and as a source of discrimination. The disease also has large economic impacts. There are many misconceptions about HIV/AIDS such as the belief that it can be transmitted by casual non-sexual contact. The disease has become subject to many controversies involving religion including the Catholic Church's position not to support condom use as prevention. It has attracted international medical and political attention as well as large-scale funding since it was identified in the 1980s.

Hong Kong

Hong Kong ( (listen); Chinese: 香港, Hong Kong Cantonese: [hœ́ːŋ.kɔ̌ːŋ] (listen)), officially the Hong Kong Special Administrative Region of the People's Republic of China and commonly abbreviated as HK, is a special administrative region on the eastern side of the Pearl River estuary in southern China. With over 7.4 million people of various nationalities in a 1,104-square-kilometre (426 sq mi) territory, Hong Kong is the world's fourth most densely populated region.

Hong Kong became a colony of the British Empire after Qing China ceded Hong Kong Island at the end of the First Opium War in 1842. The colony expanded to the Kowloon Peninsula in 1860 after the Second Opium War, and was further extended when Britain obtained a 99-year lease of the New Territories in 1898. The entire territory was transferred to China in 1997. As a special administrative region, Hong Kong's system of government is separate from that of mainland China and its people overwhelmingly identify as Hongkongers rather than Chinese.Originally a sparsely populated area of farming and fishing villages, the territory has become one of the world's most significant financial centres and commercial ports. It is the world's seventh-largest trading entity, and its legal tender (the Hong Kong dollar) is the world's 13th-most traded currency. Although the city has one of the highest per capita incomes in the world, it has severe income inequality.The territory has the largest number of skyscrapers in the world, most surrounding Victoria Harbour. Hong Kong ranks seventh on the UN Human Development Index, and has the sixth-longest life expectancy in the world. Although over 90 per cent of its population uses public transportation, air pollution from neighbouring industrial areas of mainland China has resulted in a high level of atmospheric particulates.

India

India (ISO: Bhārat), also known as the Republic of India (ISO: Bhārat Gaṇarājya), is a country in South Asia. It is the seventh largest country by area and with more than 1.3 billion people, it is the second most populous country as well as the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast, it shares land borders with Pakistan to the west; China, Nepal, and Bhutan to the northeast; and Bangladesh and Myanmar to the east. In the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives, while its Andaman and Nicobar Islands share a maritime border with Thailand and Indonesia.

The Indian subcontinent was home to the urban Indus Valley Civilisation of the 3rd millennium BCE. In the following millennium, the oldest scriptures associated with Hinduism began to be composed. Social stratification, based on caste, emerged in the first millennium BCE, and Buddhism and Jainism arose. Early political consolidations took place under the Maurya and Gupta empires; later peninsular Middle Kingdoms influenced cultures as far as Southeast Asia. In the medieval era, Judaism, Zoroastrianism, Christianity, and Islam arrived, and Sikhism emerged, all adding to the region's diverse culture. Much of the north fell to the Delhi Sultanate; the south was united under the Vijayanagara Empire. The economy expanded in the 17th century in the Mughal Empire. In the mid-18th century, the subcontinent came under British East India Company rule, and in the mid-19th under British Crown rule. A nationalist movement emerged in the late 19th century, which later, under Mahatma Gandhi, was noted for nonviolent resistance and led to India's independence in 1947.

In 2017, the Indian economy was the world's sixth largest by nominal GDP and third largest by purchasing power parity. Following market-based economic reforms in 1991, India became one of the fastest-growing major economies and is considered a newly industrialised country. However, it continues to face the challenges of poverty, corruption, malnutrition, and inadequate public healthcare. A nuclear weapons state and regional power, it has the second largest standing army in the world and ranks fifth in military expenditure among nations. India is a federal republic governed under a parliamentary system and consists of 29 states and 7 union territories. A pluralistic, multilingual and multi-ethnic society, it is also home to a diversity of wildlife in a variety of protected habitats.

Indonesia

Indonesia ( (listen) IN-də-NEE-zhə, -⁠zee-ə; Indonesian: [ɪndoˈnesia]), officially the Republic of Indonesia (Indonesian: Republik Indonesia [reˈpublik ɪndoˈnesia]), is a country in Southeast Asia, between the Indian and Pacific oceans. It is the world's largest island country, with more than seventeen thousand islands, and at 1,904,569 square kilometres (735,358 square miles), the 14th largest by land area and the 7th largest in combined sea and land area. With over 261 million people, it is the world's 4th most populous country as well as the most populous Muslim-majority country. Java, the world's most populous island, contains more than half of the country's population.

The sovereign state is a presidential, constitutional republic with an elected parliament. It has 34 provinces, of which five have special status. Jakarta, the country's capital, is the second most populous urban area in the world. The country shares land borders with Papua New Guinea, East Timor, and the eastern part of Malaysia. Other neighbouring countries include Singapore, Vietnam, the Philippines, Australia, Palau, and India's Andaman and Nicobar Islands. Despite its large population and densely populated regions, Indonesia has vast areas of wilderness that support a high level of biodiversity. The country has abundant natural resources like oil and natural gas, tin, copper and gold. Agriculture mainly produces rice, palm oil, tea, coffee, cacao, medicinal plants, spices and rubber. Indonesia's major trading partners are China, United States, Japan, Singapore and India.History of the Indonesian archipelago has been influenced by foreign powers drawn to its natural resources. It has been an important region for trade since at least the 7th century, when Srivijaya and then later Majapahit traded with entities from mainland China and the Indian subcontinent. Local rulers gradually absorbed foreign cultural, religious and political models from the early centuries and Hindu and Buddhist kingdoms flourished. Muslim traders and Sufi scholars brought Islam, while European powers brought Christianity and fought one another to monopolise trade in the Spice Islands of Maluku during the Age of Discovery. Although sometimes interrupted by the Portuguese, French and British, the Dutch were the foremost European power for much of its 350-year presence in the archipelago. In early 20th century, the concept of "Indonesia" as a nation state emerged, and independence movements began to take shape. During the decolonisation of Asia after World War II, Indonesia achieved independence in 1949 following an armed and diplomatic conflict with the Netherlands.

Indonesia consists of hundreds of distinct native ethnic and linguistic groups, with the largest—and politically dominant—ethnic group being the Javanese. A shared identity has developed, defined by a national language, ethnic diversity, religious pluralism within a Muslim-majority population, and a history of colonialism and rebellion against it. Indonesia's national motto, "Bhinneka Tunggal Ika" ("Unity in Diversity" literally, "many, yet one"), articulates the diversity that shapes the country. Indonesia's economy is the world's 16th largest by nominal GDP and the 7th largest by GDP at PPP. Indonesia is a member of several multilateral organisations, including the UN, WTO, IMF and G20. It is also a founding member of Non-Aligned Movement, Association of Southeast Asian Nations, Asia-Pacific Economic Cooperation, East Asia Summit, Asian Infrastructure Investment Bank and Organisation of Islamic Cooperation.

Italy

Italy (Italian: Italia [iˈtaːlja] (listen)), officially the Italian Republic (Italian: Repubblica Italiana [reˈpubblika itaˈljaːna]), is a country in Southern and Western Europe. Located in the middle of the Mediterranean Sea, Italy shares open land borders with France, Switzerland, Austria, Slovenia and the enclaved microstates San Marino and Vatican City. Italy covers an area of 301,340 km2 (116,350 sq mi) and has a largely temperate seasonal and Mediterranean climate. With around 61 million inhabitants, it is the fourth-most populous EU member state and the most populous country in Southern Europe.

Due to its central geographic location in Europe and the Mediterranean, Italy has historically been home to a myriad of peoples and cultures. In addition to the various ancient peoples dispersed throughout modern-day Italy, the most famous of which being the Indo-European Italics who gave the peninsula its name, beginning from the classical era, Phoenicians and Carthaginians founded colonies in insular Italy and Genoa, Greeks established settlements in the so-called Magna Graecia, while Etruscans and Celts inhabited central and northern Italy. The Italic tribe known as the Latins formed the Roman Kingdom in the 8th century BC, which eventually became a republic with a government of the Senate and the People. The Roman Republic conquered and assimilated its neighbours on the peninsula, in some cases through the establishment of federations, and the Republic eventually expanded and conquered parts of Europe, North Africa and the Middle East. By the first century BC, the Roman Empire emerged as the dominant power in the Mediterranean Basin and became the leading cultural, political and religious centre of Western civilisation, inaugurating the Pax Romana, a period of more than 200 years during which Italy's technology, economy, art and literature flourished. Italy remained the homeland of the Romans and the metropole of the Roman Empire. The legacy of the Roman Empire endured its fall and can be observed in the global distribution of culture, law, governments, Christianity and the Latin script.

During the Early Middle Ages, Italy endured sociopolitical collapse and barbarian invasions, but by the 11th century, numerous rival city-states and maritime republics, mainly in the northern and central regions of Italy, rose to great prosperity through shipping, commerce and banking, laying the groundwork for modern capitalism. These mostly independent statelets served as Europe's main trading hubs with Asia and the Near East, often enjoying a greater degree of democracy than the larger feudal monarchies that were consolidating throughout Europe; however, part of central Italy was under the control of the theocratic Papal States, while Southern Italy remained largely feudal until the 19th century, partially as a result of a succession of Byzantine, Saracen, Norman, Angevin and Aragonese conquests of the region.The Renaissance began in Italy and spread to the rest of Europe, bringing a renewed interest in humanism, science, exploration and art. Italian culture flourished, producing famous scholars, artists and polymaths such as Michelangelo, Leonardo da Vinci, Raphael, Galileo and Machiavelli. During the Middle Ages, Italian explorers such as Marco Polo, Christopher Columbus, Amerigo Vespucci, John Cabot and Giovanni da Verrazzano discovered new routes to the Far East and the New World, helping to usher in the European Age of Discovery. Nevertheless, Italy's commercial and political power significantly waned with the opening of trade routes that bypassed the Mediterranean. Centuries of infighting between the Italian city-states, such as the Italian Wars of the 15th and 16th centuries, left the region fragmented, and it was subsequently conquered and further divided by European powers such as France, Spain and Austria.

By the mid-19th century, rising Italian nationalism and calls for independence from foreign control led to a period of revolutionary political upheaval. After centuries of foreign domination and political division, Italy was almost entirely unified in 1871, establishing the Kingdom of Italy as a great power. From the late 19th century to the early 20th century, Italy rapidly industrialised, namely in the north, and acquired a colonial empire, while the south remained largely impoverished and excluded from industrialisation, fuelling a large and influential diaspora. Despite being one of the main victors in World War I, Italy entered a period of economic crisis and social turmoil, leading to the rise of a fascist dictatorship in 1922. Participation in World War II on the Axis side ended in military defeat, economic destruction and the Italian Civil War. Following the liberation of Italy and the rise of the resistance, the country abolished the monarchy, reinstated democracy, enjoyed a prolonged economic boom and, despite periods of sociopolitical turmoil (e.g. the anni di piombo, the Maxi Trial, and mani pulite) became a highly developed country.Today, Italy is considered to be one of the world's most culturally and economically advanced countries, with its economy ranking eighth-largest in the world and third in the Eurozone by nominal GDP. As an advanced economy, it has the sixth-largest worldwide national wealth. Italy owns the third-largest central bank gold reserve. It has a very high level of human development, and it stands among the top countries for life expectancy. Italian military is ranked the eighth most-powerful in the world. The country plays a prominent role in regional and global economic, military, cultural and diplomatic affairs, and it is both a regional power and a great power. Italy is a founding and leading member of the European Union and a member of numerous international institutions, including the UN, NATO, the OECD, the OSCE, the WTO, the G7, the G20, the Union for the Mediterranean, the Council of Europe, Uniting for Consensus, the Schengen Area and many more.

As a reflection of its cultural wealth, Italy is home to 54 World Heritage Sites, the most in the world, and is the fifth-most visited country.

Juventus F.C.

Juventus Football Club (from Latin: iuventūs, "youth"; Italian pronunciation: [juˈvɛntus]), colloquially known as Juve (pronounced [ˈjuːve]), is an Italian professional football club based in Turin, Piedmont. Founded in 1897 by a group of Torinese students, the club has worn a black and white striped home kit since 1903 and has played home matches in different grounds around its city, the latest being the 41,507-capacity Allianz Stadium. Nicknamed Vecchia Signora ("the Old Lady"), the club has won 34 official league titles, 13 Coppa Italia titles and eight Supercoppa Italiana titles, being the record holder for all these competitions; two Intercontinental Cups, two European Cups / UEFA Champions Leagues, one European Cup Winners' Cup, a joint national record of three UEFA Cups, two UEFA Super Cups and one UEFA Intertoto Cup. Consequently, the side leads the historical Federazione Italiana Giuoco Calcio (FIGC) ranking whilst on the international stage occupies the 4th position in Europe and the eight in the world for most confederation titles won with eleven trophies, having led the UEFA ranking during seven seasons since its inception in 1979, the most for an Italian team and joint second overall.

Founded with the name of Sport-Club Juventus, initially as an athletics club, it is the second oldest of its kind still active in the country after Genoa's football section (1893) and has competed uninterruptedly in the top flight league (reformulated as Serie A from 1929) since its debut in 1900 after changing its name to Foot-Ball Club Juventus, with the exception of the 2006–07 season, being managed by the industrial Agnelli family almost continuously since 1923. The relationship between the club and that dynasty is the oldest and longest in national sports, making Juventus the first professional sporting club in the country, having established itself as a major force in the national stage since the 1930s and at confederation level since the mid-1970s and becoming one of the first ten wealthiest in world football in terms of value, revenue and profit since the mid-1990s, being stocked in Borsa italiana since 2001.Under the management of Giovanni Trapattoni, the club won 13 trophies in the ten years before 1986, including six league titles and five international titles, and became the first to win all three competitions organised by the Union of European Football Associations: the European Champions' Cup, Cup Winners' Cup and UEFA Cup. With successive triumphs in the 1984 European Super Cup and 1985 Intercontinental Cup, it become the first and thus far only in the world to complete a clean sweep of all confederation trophies; an achievement that they revalidated with the title won in the 1999 UEFA Intertoto Cup after another successful era led by Marcello Lippi, becoming in addition the only professional Italian club to have won every ongoing honour available to the first team and organised by a national or international football association. In December 2000, Juventus was ranked seventh in the FIFA's historic ranking of the best clubs in the world and nine years later was ranked second best club in Europe during the 20th Century based on a statistical study series by the International Federation of Football History & Statistics (IFFHS), the highest for an Italian club in both.The club's fan base is the largest at national level and one of the largest worldwide. Unlike most European sporting supporters' groups, which are often concentrated around their own club's city of origin, it is widespread throughout the whole country and the Italian diaspora, making Juventus a symbol of anticampanilismo ("anti-parochialism") and italianità ("Italianness"). The club has also provided the most players to the Italy national team—mostly in official competitions—who often formed the group that led the Azzurri squad to international success, most importantly in the 1934, 1982 and 2006 FIFA World Cups.

Kuwait

Kuwait ( (listen); Arabic: الكويت‎ al-Kuwait, Gulf Arabic pronunciation: [ɪl‿ɪkweːt] or [lɪkweːt]), officially the State of Kuwait (Arabic: دولة الكويت‎ Dawlat al-Kuwait), is a country in Western Asia. Situated in the northern edge of Eastern Arabia at the tip of the Persian Gulf, it shares borders with Iraq and Saudi Arabia. As of 2016, Kuwait has a population of 4.5 million people: 1.3 million are Kuwaitis and 3.2 million are expatriates. Expatriates account for 70% of the population.Oil reserves were discovered in commercial quantities in 1938. From 1946 to 1982, the country underwent large-scale modernization. In the 1980s, Kuwait experienced a period of geopolitical instability and an economic crisis following the stock market crash. In 1990, Kuwait was invaded, and later annexed, by Saddam's Iraq. The Iraqi occupation of Kuwait came to an end in 1991 after military intervention by a military coalition led by the United States. Kuwait is a major non-NATO ally of the United States. It is also a major ally of ASEAN, while maintaining a strong relationship with China.Kuwait is a constitutional sovereign state with a semi-democratic political system. Kuwait has a high-income economy backed by the world's sixth largest oil reserves. The Kuwaiti dinar is the highest valued currency in the world. According to the World Bank, the country has the fourth highest per capita income. The Constitution was promulgated in 1962. Kuwait is home to the largest opera house in the Middle East. The Kuwait National Cultural District is a member of the Global Cultural Districts Network.

Luxembourg

Luxembourg ( (listen); Luxembourgish: Lëtzebuerg [ˈlətsəbuə̯ɕ] (listen); French: Luxembourg; German: Luxemburg), officially the Grand Duchy of Luxembourg, is a small landlocked country in western Europe. It is bordered by Belgium to the west and north, Germany to the east, and France to the south. Its capital, Luxembourg City, is one of the three official capitals of the European Union (together with Brussels and Strasbourg) and the seat of the European Court of Justice, the highest judicial authority in the EU. Its culture, people, and languages are highly intertwined with its neighbours, making it essentially a mixture of French and German cultures, as evident by the nation's three official languages: French, German, and the national language, Luxembourgish (sometimes considered a dialect of German). The repeated invasions by Germany, especially in World War II, resulted in the country's strong will for mediation between France and Germany and, among other things, led to the foundation of the European Union.With an area of 2,586 square kilometres (998 sq mi), it is one of the smallest sovereign states in Europe. In 2018, Luxembourg had a population of 602,005, which makes it one of the least-populous countries in Europe, but by far the one with the highest population growth rate. Foreigners account for nearly half of Luxembourg's population. As a representative democracy with a constitutional monarch, it is headed by Grand Duke Henri and is the world's only remaining grand duchy. Luxembourg is a developed country, with an advanced economy and one of the world's highest GDP (PPP) per capita. The City of Luxembourg with its old quarters and fortifications was declared a UNESCO World Heritage Site in 1994 due to the exceptional preservation of the vast fortifications and the old city.The history of Luxembourg is considered to begin in 963, when count Siegfried I acquired a rocky promontory and its Roman-era fortifications known as Lucilinburhuc, ′little castle′, and the surrounding area from the Imperial Abbey of St. Maximin in nearby Trier.

Siegfried's descendants increased their territory through marriage, war and vassal relations. At the end of the 13th century, the Counts of Luxembourg reigned over a considerable territory.

In 1308, Henry VII, Count of Luxembourg became King of the Germans and Holy Roman Emperor. The House of Luxembourg produced four Holy Roman Emperors during the high Middle Ages. In 1354, Charles IV elevated the County to the Duchy of Luxembourg. Since Sigismund had no male heir, the Duchy became part of the Burgundian Circle and then one of the Seventeen Provinces of the Habsburg Netherlands.

Over the centuries, the City and Fortress of Luxembourg, of great strategic importance situated between the Kingdom of France and the Habsburg territories, was gradually built up to be one of the most reputed fortifications in Europe. After belonging to both the France of Louis XIV and the Austria of Maria Theresia, Luxembourg became part of the First French Republic and Empire under Napoleon.The present-day state of Luxembourg first emerged at the Congress of Vienna in 1815. The Grand-Duchy, with its powerful fortress, became an independent state under the personal possession of William I of the Netherlands with a Prussian garrison to guard the city against another invasion from France. In 1839, following the turmoil of the Belgian Revolution, the purely French-speaking part of Luxembourg was ceded to Belgium and the Luxembourgish-speaking part (except the Arelerland, the area around Arlon) became what is the present state of Luxembourg.Luxembourg is a founding member of the European Union, OECD, United Nations, NATO, and Benelux. The city of Luxembourg, which is the country's capital and largest city, is the seat of several institutions and agencies of the EU. Luxembourg served on the United Nations Security Council for the years 2013 and 2014, which was a first in the country's history. As of 2018, Luxembourgish citizens had visa-free or visa-on-arrival access to 186 countries and territories, ranking the Luxembourgish passport 5th in the world, tied with Austria, the Netherlands, Norway, Portugal, the United Kingdom and the United States.

Mexico

Mexico (Spanish: México [ˈmexiko] (listen); Nahuatl languages: Mēxihco), officially the United Mexican States (Spanish: Estados Unidos Mexicanos, listen ), is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Covering almost 2,000,000 square kilometres (770,000 sq mi), the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the eleventh most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity that is also the capital city and its most populous city. Other metropolises in the state include Guadalajara, Monterrey, Puebla, Toluca, Tijuana and León.

Pre-Columbian Mexico dates to about 8000 BC and is identified as one of five cradles of civilization and was home to many advanced Mesoamerican civilizations such as the Olmec, Toltec, Teotihuacan, Zapotec, Maya, and Aztec before first contact with Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its politically powerful base in Mexico-Tenochtitlan (part of Mexico City), which was administered as the viceroyalty of New Spain. Three centuries later, the territory became a nation state following its recognition in 1821 after the Mexican War of Independence. The post-independence period was tumultuous, characterized by economic inequality and many contrasting political changes. The Mexican–American War (1846–1848) led to a territorial cession of the extant northern territories to the United States. The Pastry War, the Franco-Mexican War, a civil war, two empires, and the Porfiriato occurred in the 19th century. The Porfiriato was ended by the start of the Mexican Revolution in 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the country's current political system as a federal, democratic republic.

Mexico has the 15th largest nominal GDP and the 11th largest by purchasing power parity. The Mexican economy is strongly linked to those of its 1994 North American Free Trade Agreement (NAFTA) partners, especially the United States. In 1994, Mexico became the first Latin American member of the Organisation for Economic Co-operation and Development (OECD). It is classified as an upper-middle income country by the World Bank and a newly industrialized country by several analysts. The country is considered both a regional power and a middle power, and is often identified as an emerging global power. Due to its rich culture and history, Mexico ranks first in the Americas and seventh in the world for number of UNESCO World Heritage Sites. Mexico is an ecologically megadiverse country, ranking fourth in the world for its biodiversity. Mexico receives a huge number of tourists every year: in 2018, it was the sixth most-visited country in the world, with 39 million international arrivals. Mexico is a member of the United Nations (UN), the World Trade Organization (WTO), the G8+5, the G20, the Uniting for Consensus group of the UN, and the Pacific Alliance trade bloc.

Slovenia

Slovenia ( (listen) sloh-VEE-nee-ə; Slovene: Slovenija [slɔˈʋèːnija]), officially the Republic of Slovenia (Slovene: Republika Slovenija , abbr.: RS), is a sovereign state located in southern Central Europe at a crossroads of important European cultural and trade routes. It is bordered by Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the southeast, and the Adriatic Sea to the southwest. It covers 20,273 square kilometers (7,827 sq mi) and has a population of 2.07 million. One of the successor states of the former Yugoslavia, Slovenia is a parliamentary republic and a member of the United Nations, of the European Union, and of NATO. The capital and largest city is Ljubljana.Slovenia has a mostly mountainous terrain with a mainly continental climate, with the exception of the Slovene Littoral, which has a sub-Mediterranean climate, and of the northwest, which has an Alpine climate. Additionally, the Dinaric Alps and the Pannonian Plain meet on the territory of Slovenia. The country, marked by a significant biological diversity, is one of the most water-rich in Europe, with a dense river network, a rich aquifer system, and significant karst underground watercourses. Over half of the territory is covered by forest. The human settlement of Slovenia is dispersed and uneven.Slovenia has historically been the crossroads of Slavic, Germanic, and Romance languages and cultures. Although the population is not homogeneous, Slovenes comprise the majority. The South Slavic language Slovene is the official language throughout the country. Slovenia is a largely secularized country, but Catholicism and Lutheranism have significantly influenced its culture and identity. The economy of Slovenia is small, open and export-oriented and has been strongly influenced by international conditions. It has been severely hurt by the Eurozone crisis which started in 2009. The main economic field is services, followed by industry and construction.Historically, the current territory of Slovenia has formed part of many different states, including the Roman Empire, Byzantine Empire, Carolingian Empire and the Holy Roman Empire, the Habsburg Monarchy, the Republic of Venice, the French-administered Illyrian Provinces of Napoleon I, the Austrian Empire and Austria-Hungary. In October 1918 the Slovenes exercised self-determination for the first time by co-founding the State of Slovenes, Croats and Serbs. In December 1918 they merged with the Kingdom of Serbia into the Kingdom of Serbs, Croats and Slovenes (renamed Kingdom of Yugoslavia in 1929).

During World War II (1939–1945) Germany, Italy, and Hungary occupied and annexed Slovenia (1941–1945), with a tiny area transferred to the Independent State of Croatia, a Nazi puppet state. In 1945 Slovenia became a founding member of the Federal People's Republic of Yugoslavia, renamed in 1963 as the Socialist Federal Republic of Yugoslavia. In the first years after World War II this state was initially allied with the Eastern Bloc, but it never subscribed to the Warsaw Pact and in 1961 became one of the founders of the Non-Aligned Movement.

In June 1991, after the introduction of multi-party representative democracy, Slovenia split from Yugoslavia and became an independent country. In 2004, it entered NATO and the European Union; in 2007 became the first formerly communist country to join the Eurozone; and in 2010 it joined the OECD, a global association of high-income developed countries.

UEFA Euro 2016

The 2016 UEFA European Championship, commonly referred to as UEFA Euro 2016 or simply Euro 2016, was the 15th UEFA European Championship, the quadrennial international men's football championship of Europe organised by UEFA. It was held in France from 10 June to 10 July 2016. Spain were the two-time defending champions, having won the 2008 and 2012 tournaments, but were eliminated in the round of 16 by Italy. Portugal won the tournament for the first time, following a 1–0 victory after extra time over the host team, France, in the final played at the Stade de France.

For the first time, the European Championship final tournament was contested by 24 teams, having been expanded from the 16-team format used since 1996. Under the new format, the finalists contested a group stage consisting of six groups of four teams, followed by a knockout phase including three rounds and the final. Nineteen teams – the top two from each of the nine qualifying groups and the best third-placed team – joined France in the final tournament, who qualified automatically as host; a series of two-legged play-off ties between the remaining third-placed teams in November 2015 decided the last four finalist spots.

France was chosen as the host nation on 28 May 2010, after a bidding process in which they beat Italy and Turkey for the right to host the 2016 finals. The matches were played in ten stadiums in ten cities: Bordeaux, Lens, Lille Métropole, Décines-Charpieu, Marseille, Nice, Paris, Saint-Denis, Saint-Étienne, and Toulouse. It was the third time that France hosted the finals, after the inaugural tournament in 1960 and the 1984 finals.

As the winners, Portugal earned the right to compete at the 2017 FIFA Confederations Cup in Russia.

United States

The United States of America (USA), commonly known as the United States (U.S. or US) or America, is a country composed of 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles (9.8 million km2), the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe's 3.9 million square miles (10.1 million km2). With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico. The State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean. The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The extremely diverse geography, climate, and wildlife of the United States make it one of the world's 17 megadiverse countries.Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century. The United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, and the subsequent Declaration of Independence in 1776. The war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties. The United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, and gradually admitting new states until it spanned the continent by 1848.During the second half of the 19th century, the Civil War led to the abolition of slavery. By the end of the century, the United States had extended into the Pacific Ocean, and its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power. The United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, and a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U.S. Moon landing. The end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower.The United States is the world's oldest surviving federation. It is a federal republic and a representative democracy. The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States (OAS), and other international organizations. The United States is a highly developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for approximately a quarter of global GDP. The U.S. economy is largely post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U.S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country.Despite wide income and wealth disparities, the United States continues to rank very high in measures of socioeconomic performance, including average wage, human development, per capita GDP, and worker productivity. The United States is the foremost military power in the world, making up a third of global military spending, and is a leading political, cultural, and scientific force internationally.

Uttar Pradesh

Uttar Pradesh (; IAST: Uttar Pradeś [ˈʊtːəɾ pɾəˈdeːʃ] (listen)) is a state in northern India. With over 200 million inhabitants, it is the most populous state in India as well as the most populous country subdivision in the world. It is located in the north-central region of the Indian subcontinent. It was created on 1 April 1937 as the United Provinces of Agra and Oudh during British rule, and was renamed Uttar Pradesh in 1950. The state is divided into 18 divisions and 75 districts with the capital being Lucknow. The main ethnic group is the Hindavi people, forming the demographic plurality. On 9 November 2000, a new state, Uttarakhand, was carved out from the state's Himalayan hill region. The two major rivers of the state, the Ganga and Yamuna, join at Allahabad (Prayagraj) and then flow as the Ganga further east. Hindi is the most widely spoken language and is also the official language of the state.

The state is bordered by Rajasthan to the west, Haryana, Himachal Pradesh and Delhi to the northwest, Uttarakhand and Nepal to the north, Bihar to the east, Madhya Pradesh to the south, and touches the states of Jharkhand and Chhattisgarh to the southeast. It covers 243,290 square kilometres (93,933 sq mi), equal to 7.33% of the total area of India, and is the fourth-largest Indian state by area. The economy of Uttar Pradesh is the fourth-largest state economy in India with ₹15.79 lakh crore (US$220 billion) in gross domestic product and a per capita GDP of ₹57,480 (US$800). Agriculture and service industries are the largest parts of the state's economy. The service sector comprises travel and tourism, hotel industry, real estate, insurance and financial consultancies. President's rule has been imposed in Uttar Pradesh ten times since 1968, for different reasons and for a total of 1,700 days.The natives of the state are generally called Uttar Bhartiya, or more specifically either Awadhi, Bageli, Bhojpuri, Braji, Bundeli, Kannauji, or Rohilkhandi depending upon their region of origin. Hinduism is practised by more than three-fourths of the population, with Islam being the next largest religious group. Uttar Pradesh was home to powerful empires of ancient and medieval India. The state has several historical, natural, and religious tourist destinations, such as Agra, Ayodhya, Vrindavan (Mathura), Varanasi and Allahabad.

Vietnam

Vietnam (UK: , US: (listen); Vietnamese: Việt Nam pronounced [vîət nāːm] (listen)), officially the Socialist Republic of Vietnam (Vietnamese: Cộng hòa xã hội chủ nghĩa Việt Nam), is the easternmost country on the Indochina Peninsula. With an estimated 94.6 million inhabitants as of 2016, it is the 15th most populous country in the world. Vietnam is bordered by China to the north, Laos and Cambodia to the west, part of Thailand to the southwest, and the Philippines, Malaysia, and Indonesia across the South China Sea to the east and southeast. Its capital city has been Hanoi since the reunification of North and South Vietnam in 1976, while its most populous city is Ho Chi Minh City.

During the 3rd century BC, ancient Vietnamese people inhabited modern-day northern Vietnam and established the state of Âu Lạc. The independent state was annexed by Nam Việt in 179 BC. Nam Việt was subsequently annexed by the Han Empire and became part of Imperial China for over a millennium from 111 BC to 939 AD. An independent Vietnamese state emerged in 939 following Vietnamese victory in the battle of Bạch Đằng against the Southern Han. Successive Vietnamese imperial dynasties flourished as the nation expanded geographically and politically into Southeast Asia, until the Indochina Peninsula was colonised by the French in the mid-19th century.

French Indochina saw the Japanese occupation in 1940 amidst the escalation of World War II. Following Japanese defeat in 1945, the Vietnamese fought French rule in the First Indochina War. On 2 September 1945, Vietnamese revolutionary leader Hồ Chí Minh declared Vietnam's independence from France and therefrom established a provisional communist state. After nine years of war, the Vietnamese declared victory in the decisive battle of Điện Biên Phủ in 1954. The nation was thereafter divided into two rival states, communist North—the Democratic Republic of Vietnam, and anti-communist South—the Republic of Vietnam. Conflicts intensified in the Vietnam War with extensive US intervention in support of South Vietnam from 1965 to 1973. The war ended with North Vietnamese victory in 1975.

North and South Vietnam were then reunified under a communist government in 1976. The newly established country remained impoverished and politically isolated until 1986, when the Communist Party initiated a series of economic and political reforms that facilitated Vietnamese integration into the world economy. By 2010, Vietnam had established diplomatic relations with 178 countries. Since 2000, Vietnam's GDP growth rate has been among the highest in the world. Its successful economic reforms resulted in its joining the WTO in 2007. Vietnam is also a member of the Association of Southeast Asian Nations (ASEAN), Asia-Pacific Economic Cooperation (APEC) and the Organisation Internationale de la Francophonie (OIF).

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