Noisy, vibrant and truly multicultural, London is a megalopolis of people, ideas and frenetic energy. The capital and largest city of England, and of the wider United Kingdom, it is also the largest city in Western Europe. Situated on the River Thames in South-East England, Greater London has an official population of a little over 8 million, but the estimate of between 12 and 14 million people in the greater metropolitan area better reflects its size and importance. Considered one of the world's leading "global cities", London remains an international capital of culture, music, education, fashion, politics, finance and trade.
The name "London" used to refer only to the once-walled "Square Mile" of the original Roman (and later medieval) city (confusingly called the "City of London" or just "The City"). Today, London has taken on a much larger meaning to include all of the vast central parts of the modern metropolis, with the city having absorbed numerous surrounding towns and villages over the centuries, including large portions of the surrounding "home counties", one of which - Middlesex - being completely consumed by the growing metropolis. The term Greater London embraces Central London together with all the outlying suburbs that lie in one continuous urban sprawl within the lower Thames Valley. Though densely populated, London retains large swathes of green parkland and open space, even within the city centre.