INSIDE WW2 GERMAN U-BOAT BASE IN LORIENT The largest of the five U-Boat sites built in western France by German forces during WW2, Lorient maintains a huge footprint on the Keroman peninsula with three main bunker sites – Keroman I, II, and III - plus dry docks, and two cathedral-like ‘Dombunker’ for protecting and servicing U-Boats out of the water. A fourth bunker, Keroman IVa was planned and building work was started – there’s a wall which can be seen connecting to K3 – but it was never finis