The Maunsell Forts were small fortified towers built in the Thames and Mersey estuaries during the Second World War to help defend the United Kingdom. They were named after their designer, Guy Maunsell. The forts were decommissioned in the late 1950s and later used for other activities. One became the Principality of Sealand; boats visit the remaining forts occasionally, and a consortium called Project Redsands is planning to conserve the fort situated at Redsand.
Maunsell Forts ... These sci-fi towers were constructed in the Thames estuary to protect England's coast from German air raids during World War II. After being abandoned in 1956, the forts were briefly used to broadcast offshore radio stations.