London is the capital city of England and the United Kingdom. It is the most populous region, urban zone and metropolitan area in the United Kingdom. Standing on the River Thames, London has been a major settlement for two millennia, its history going back to its founding by the Romans, who named it Londinium.
London is one of the world's leading financial centres and has the fifth-or sixth-largest metropolitan area GDP in the world depending on measurement. London is a world cultural capital. It is the world's most-visited city as measured by international arrivals and has the world's largest city airport system measured by passenger traffic. London's 43 universities form the largest concentration of higher education in Europe. In 2012, London became the first city to host the modern Summer Olympic Games three times.
London has a diverse range of peoples and cultures, and more than 300 languages are spoken within its boundaries. London had an official population of 8,308,369 in 2012, making it the most populous municipality in the European Union.
London contains four World Heritage Sites: the Tower of London; Kew Gardens; the site comprising the Palace of Westminster, Westminster Abbey, and St Margaret's Church; and the historic settlement of Greenwich (in which the Royal Observatory, Greenwich marks the Prime Meridian, 0° longitude, and GMT). Other famous landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, St Paul's Cathedral, Tower Bridge, Trafalgar Square, and The Shard. London is home to numerous museums, galleries, libraries, sporting events and other cultural institutions, including the British Museum, National Gallery, Tate Modern, British Library and 40 West End theatres. The London Underground is the oldest underground railway network in the world.