This castle, just outside of Prague, Czech Republic, was built for an arcane purpose. It wasn’t constructed as a home or fortification, but because there was a giant hole in the ground that was allegedly the “gateway to hell.” Thus, a castle with a chapel was needed to contain the horrors that would crawl out of the hole.

So, of course, the Nazis needed to possess this castle and conduct evil human experiments, which they did on prisoners of war and the locals. After the war, the allies found weird experiments, ghostly encounters and the bodies of executed Nazi soldiers.