The following outline is provided as an overview of and topical guide to London: London – capital and most populous city of England, Great Britain, and the United Kingdom. On the River Thames in the south east of the island of Great Britain, London has been a major settlement for two millennia. It was founded by the Romans, who named it Londinium. London is a cultural capital and leading global city in the arts, commerce, education, entertainment, fashion, finance, healthcare, media, professional services, research and development, tourism, and transport. It is the world's financial capital and has the fifth-or sixth-largest metropolitan area GDP in the world.