London is the capital and most populous city of England and the United Kingdom. Standing on the River Thames in the southeast of Great Britain, London has been a major settlement for two millennia. The bulk of this conurbation forms Greater London, a region of England governed by the Mayor of London and the London Assembly. The conurbation also covers two English counties: the small district of the City of London and the county of Greater London. The latter constitutes the vast majority of London, though historically it was split between Middlesex (a now abolished county), Essex, Surrey, Kent, and Hertfordshire.
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 one of the world's leading financial centers 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 is the world’s leading investment destination, hosting more international retailers and ultra-high-net-worth individuals than any other city. London’s 43 universities form the largest concentration of higher education institutes in Europe, and a 2014 report placed it first in the world university rankings. According to the report, London also ranks first in the world in software, multimedia development, and design, and shares the first position in technology readiness. In 2012, London became the first city to host the modern Summer Olympic Games three times.