Louis Joubert Lock

The Louis Joubert Lock, also known as the Normandie Dock – after the large ocean liner that provided the impetus for the facility to be built, is a lock and major dry dock located in the port of Saint-Nazaire in Loire-Atlantique, northwestern France.

Owned by the Port authority of Nantes-Saint-Nazaire, its strategic importance as a major naval construction and maintenance asset after its completion in 1934 resulted in it becoming the main target of the St. Nazaire Raid; the 1942 British Army Commando raid successfully prevented German battleships, such as Tirpitz, from accessing its maintenance facilities while operating in the Atlantic Ocean.

Source: Wikipedia