Saint-Nazaire submarine base

Construction of the U-boat base in St. Nazaire began in 1941 under German occupation, utilizing numerous forced laborers. 480,000 cubic meters of reinforced concrete were used for the construction, covering an area of 39,200 square meters. Initially conceived as a base for two U-boat flotillas, the facility was expanded in 1942 into a war shipyard, which included workshops, medical facilities, and canteens. As part of the Atlantic Wall, further bunker systems and depots were built in the surrounding area. Saint-Nazaire was of strategic importance due to its large dock, the only one on the Atlantic coast suitable for battleships like the Bismarck. This led to numerous air raids and a British commando operation in March 1942, which, however, only destroyed the dock entrance.