London

London contains four World Heritage Sites: the Tower of London; Kew Gardens; the site comprising the Palace of Westminster, Westminster Abbey, and St Margaret's Church; and the historic settlement of Greenwich (in which the Royal Observatory marks the Prime Meridian (0° longitude) and GMT).Other famous landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, 30 St Mary Axe ("The Gherkin"), St Paul's Cathedral, Tower Bridge, Trafalgar Square and Wembley Stadium. London is home to numerous museums, galleries, libraries, sporting events and other cultural institutions including the British Museum, National Gallery, British Library, Wimbledon and 40 theatres.London's Chinatown is the largest in Europe.The London Underground network is the oldest underground railway network in the world and the most extensive after the Shanghai Metro.