HTML is the standard markup language used to create web pages. It uses tags to define headings, paragraphs, links, images and other page elements. HTML documents have a basic structure including <html>, <head>, <title> and <body> tags. Elements are nested within each other and consist of a starting and closing tag with content in between. Attributes provide additional information about elements. HTML pages are viewed in web browsers, which use the tags to render the content but do not display the tags themselves.