The U-Boat Bunker Keroman 3 (K3) is a massive concrete structure located in Lorient, France, built during World War II as part of the German U-boat base complex. Constructed by the Kriegsmarine between 1941 and 1943, this fortified shelter was designed to protect submarines from Allied air raids and enable rapid deployment. The bunker features thick reinforced concrete walls and massive blast doors, characteristic of German military engineering of the era.
The facility played a crucial role in the Battle of the Atlantic, serving as a strategic hub for U-boat operations in the Atlantic theater. After the war, the French Navy continued to use the bunker until the 1990s, demonstrating its enduring military value. Today, K3 stands as a preserved historical monument, offering visitors insight into the naval warfare of World War II and Lorient's significance as a strategic port during the conflict.