Greenwich is notable for its maritime history and for giving its name to the Greenwich Meridian (0° longitude) and Greenwich Mean Time (GMT).
Greenwich Mean Time is mean solar time at the Royal Observatory in Greenwich, London. GMT was formerly used as the international civil time standard, now superseded in that function by Coordinated Universal Time (UTC).
Greenwich is generally described as being part of South-east London. It is also one of the five boroughs of the London Docklands, connected to areas with docks of London historically by river and today to Canary Wharf and other buildings by the East London Line.