The Fort du Roule is a collection of French and German fortifications built in the nineteenth and twentieth centuries on the Roule mountain in Cherbourg.
The first fortifications were built in 1793 to protect the Bay of Cherbourg from English attacks. The current fort, at the top of the mountain, was built between 1853 and 1857 under Napoleon III. In 1928, the Navy built extensive tunnels under it to store equipment. During the Second World War, the Todt Organisation built several tunnels, installed casemates for artillery, and built gun emplacements.
Wikipedia https://en.wikipedia.org/wiki/Fort_du_Roule
Wikipedia https://fr.wikipedia.org/wiki/Fort_du_Roule
Address Cherbourg-Octeville 50100, France
Coordinates 49°37'49.797" N -1°36'49.329" E