The Cap Gris Nez area between Boulogne-sur-Mer and Calais was one of the most heavily fortified areas of occupied France and boasted now infamous batteries such as Todt, Grosser Kurfurst, and Lindemann with many supporting strongpoints linking them along the coastline.

Behind them, inland, was a rail line network where massive railway guns would operate. Krupp-built K5 guns were positioned here from 1940 onwards originally to provide fire support for Operation Sealion (the German invasion of Britain) and later to fire 28cm shells across the English Channel to Dover.

There were three Dombunkers built in the area and all three survive today. This one, at Stp Bismark to the east of the town of Marquise, stands in the centre of a railway yard for a large quarry operation.
Close inspection is not possible without permission as it is still in use and at a dangerous location, but you can still see the original doors are in place.

A second Dombunker is located on the edge of Wimereux to the south – at Wn208 Gabelweihe – and stands amongst a housing estate. It is used for local industry and access is with permission only.

The third Dombunker can be seen at Strongpoint Stp89 Fulda in the western outskirts of Calais and that site also features a large ammunition storage bunker and personnel shelter for those operating the gun.