Thames Barrier

• Thames Barrier
  The world's largest movable flood barrier. It spans 520 metres (a third of a mile) across the Thames where it protects Britain's capital city from tidal flooding.The Visitors Centre on the South Bank is open daily
  Location: Woolwich Dockyard - Charlton - Tube
  Postcode: SE18 9BU
  Telephone: 020 8305 4188
  URL: http://www.environment-agency.gov.uk/