Pharmacognosy, Medicinal Plants and Natural Products

London is the capital and largest city of England and the United Kingdom. It stands on the River Thames in south-east England at the head of a 50-mile (80 km) estuary down to the North Sea, and has been a major settlement for two millennia. The City of London, its ancient core and financial center, was founded by the Romans as Londinium and retains boundaries close to its medieval ones. Since the 19th century, "London" has also referred to the metropolis around this core, historically split between the counties of Middlesex, Essex, Surrey, Kent, and Hertfordshire, which largely makes up Greater London, the region governed by the Greater London Authority.

The City of Westminster, to the west of the City, has for centuries held the national government and parliament. Greater London Built-up Area is the fourth most populous in Europe, after Istanbul, Moscow and Paris, with 9,787,426 inhabitants at the 2011 census. The London metropolitan area is the third-most populous in Europe after Istanbul's and Moscow's, with 14,040,163 inhabitants in 2016. London has four World Heritage Sites: the Tower of London; Kew Gardens; the Palace of Westminster, along with Westminster Abbey, and St Margaret's Church; and the historic settlement in Greenwich, where the Royal Observatory, Greenwich defines the Prime Meridian (0° longitude) and Greenwich Mean Time. Other landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, St Paul's Cathedral, Tower Bridge and Trafalgar Square. It has numerous museums, galleries, libraries and sporting venues, including the British Museum, National Gallery, Natural History Museum, Tate Modern, British Library and West End theatres. The London Underground is the oldest rapid transit system in the world.