London is the capital and largest city of both England and the United Kingdom, as well as the largest city within the European Union.Standing on the River Thames in the south-east of England, at the head of its 50-mile (80 km) estuary leading to the North Sea, London has been a major settlement for two millennia. Londinium was founded by the Romans. The City of London, London’s ancient core − an area of just 1.12 square miles (2.9 km2) and colloquially known as the Square Mile − retains boundaries that follow closely its medieval limits. The City of Westminster is also an Inner London borough holding city status. Greater London is governed by the Mayor of London and the London Assembly.

London is one of the leading tourist destinations in the world and in 2015 was ranked as the most visited city in the world with over 65 million visits. It is also the top city in the world by visitor cross-border spending, estimated at US$20.23 billion in 2015. Tourism is one of London’s prime industries, employing the equivalent of 350,000 full-time workers in 2003, and the city accounts for 54% of all inbound visitor spending in the UK. As of 2016 London is the world top city destination as ranked by TripAdvisor users.

In 2015 the top most-visited attractions in the UK were all in London. The top 10 most visited attractions were: (with visits per venue)

The British Museum – The National Gallery – The Natural History Museum (South Kensington) – The Southbank Centre – Tate Modern:

The Victoria and Albert Museum (South Kensington) – The Science Museum – Somerset House – The Tower of London – The National Portrait Gallery

The number of hotel rooms in London in 2015 stood at 138,769, and is expected to grow over the years.