The largest city, urban zone and metropolitan area in the United Kingdom, and the European Union by most measures. Located 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’s ancient core, the City of London, largely retains its square-mile mediaeval boundaries. Since at least the 19th century, the name London has also referred to the metropolis developed around this core. The bulk of this conurbation forms the London region and the Greater London administrative area, governed by the elected Mayor of London and the London Assembly.

London is a leading global city, with strengths in the arts, commerce, education, entertainment, fashion, finance, healthcare, media, professional services, research and development, tourism and transport all contributing to its prominence. It is the world’s leading financial centre alongside New York City and has the fifth- or sixth-largest metropolitan area GDP in the world depending on measurement. London has been described as a world cultural capital. It is the world’s most-visited city 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.