The National Gallery

Stately but somehow not grand in its position perched above Trafalgar Square — and seemingly oblivious to the sky-reaching phallus topped by Lord Nelson just meters away — Britain's principal art institution houses more than 2,000 paintings, from the 13th century through the early 1900s. In an afternoon's wander within these walls you'll find da Vinci, Piero della Francesca, Mantegna, Vermeer, Van Eyck, Velásquez, El Greco, Rembrandt, Ingres, Titian, Veronese and, among many others, 'locals' such as Constable, Stubbs and Gainsborough. Good catering too.