The Maunsell Sea Forts were small fortified towers built in the Thames and Mersey estuaries during World War II to help defend the United Kingdom. They take their name from their designer Guy Maunsell, a civil engineering born in India. Maunsell built both sea forts and army forts; each type was floated into the open ocean and attached to the sea floor. The two-pillared sea forts were designed to deter minelaying operations and extend the range of naval radar, called sea forts because they were operated by the navy. The army forts (run by the army) were primarily used for anti-aircraft defense, and were much larger structures. 7 interconnected steel platforms were built on legs above the ocean, with 5 gun towers surrounding the command center, and a searchlight tower some distance away. They were a military success, shooting down some 22 aircraft and 30 flying bombs.

Shivering Sands was one of the army forts. It sits 9.2 miles off the coast of the UK, a location it was floated to in 1943. It was officially abandoned in 1958, and sits today as rusting remnant of the war. Only six towers are visible in the photographs because one tower collapsed when struck by a boat in bad weather. Shivering Sands has been used as the base of a pirate radio station and was home to weather research equipment. Artist Stephen Turner spent 6 weeks living by himself in the searchlight tower of Shivering Sands in 2005. Judging by the pictures, that would be decidedly creepy.