Batterie Oldenburg was one of the main cross-channel coastal batteries constructed by the Germans in around 1940. It is located just East of Calais beyond the sand dunes near the old Hovercraft pad. The two 21cm guns were mounted in huge casemates, known as 'Turm Ost' and 'Turm West'. Inside the concrete structures were the emplacements for the guns with many rooms on two levels including shell stores and accommodation behind. Turm Ost remains complete, but Turm West has suffered from an explosion inside which has destroyed the floor and some of the internal rooms. There are many other bunkers on the battery site, most of which are open, including a hospital and Fire-command post.
These bunkers are open and can be visited, with care and the appropriate equipment.
Exterior of 'Turm West' Casemate