​​Roquetoire​ Bunker

​​This site was a complementary construction to that of La Coupole, as the Audomarois (the region of Saint-Omer) offered the German forces one of the most strategic points for the use of these new technologies.

The Roquetoire site has a fortress-like structure, with walls 22 metres wide, 35 metres long and 3.5 metres thick It is a unique site, specially built to accommodate the Umspannwerk C (transformer station C). The construction work was carried out by Russian and Ukrainian prisoners between the end of 1943 and the end of May 1944.

The bunker housed rooms for the control of the doors, ventilation, fuel storage, and a room for transmissions. There were also two types of lodgings, one for the officers and a second room that could accommodate 25 soldiers.

​The highly secret plans of the site were photographed by a Resistance fighter and sent to London. The Umspannwerk C in Roquetoire was never fully operational. At Wizernes, the location of Bauvorhaben 21, the V2 rockets were to be stored in tunnels hidden in a chalk quarry. After storage, the rockets were to be transported to a preparation room and then taken outside for firing. The Wizernes site was to be self-sufficient with generators, offices, a hospital, etc., as would be the building in Roquetoire. These large buildings were a major target for the Allies, who carried out massive bombing raids throughout the area. As a result, these sites were never fully operational. The Roquetoire site was spared from bombing. Its only military function was as a storage place for vehicles and ammunition.

​Although occupying forces took some of the equipment with them when they left in a hurry after the liberation, in 1946, the French recovered material for the Vernon space research centre. The site was then used as a public dump, but since 1989 has been protected by a family of enthusiasts.

Today, the site is not open to the public.​