The Thames Estuary Army Forts, designed by Guy Maunsell, were constructed in 1942 to provide anti-aircraft fire within the Thames Estuary area (in Britain). Each fort consisted of seven towers with a walkway connecting them all to the central control tower. The fort, when viewed as a whole, comprised one Bofors tower, a control tower, four gun towers and a searchlight tower.
Two of the forts, the Red Sands and Shivering Sands Forts, are still standing. They have been used as pirate radio stations during the 60’s and 70’s, but since then have remained abandoned.