In the heart of northern Germany stands a structure that still inspires awe today: the Valentin submarine bunker. A gigantic concrete colossus, built during World War II – intended as a protected factory for state-of-the-art submarines. But what was meant to be built here was never used. Beneath meters of concrete lies a story of megalomania, technological obsession, and unimaginable human suffering. Thousands of forced laborers had to construct this place under extreme conditions many of them d