The submarine base of Saint-Nazaire is a large fortified U-boat pen built by the Germans during the Second World War in Saint Nazaire.
It is one of the five large submarine bases built by the Third Reich in Occupied France.
More information at mairie-saintnazaire.fr http://www.mairie-saintnazaire.fr/eng/the-submarine-base/
Address Saint-Nazaire 44600, France
Coordinates 47°16'33.404" N -2°12'9.381" E