Old Ruins to Explore in Bremen

Valentin submarine pens are the second-largest above-ground bunker in Europe and the most visible legacy of three major Nazi armament projects that have transformed a predominantly agricultural region since the mid-1930s. The factory was under construction from 1943 to March 1945 using forced labor, but was damaged by air-raids and unfinished by the end of the war. The Valentin factory was the largest fortified U-boat facility in Germany and was second only to those built at Brest in France.