Set in Bremen, Denkort Bunker Valentin is 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. Little evidence remains today of the original fuel depot projects of the 1930s, the camps or the massive construction site. All that remains is the bunker itself, an unmistakable icon of the Nazi war machinery.