On the Way to Underground

Hitler had a plan to build an underground city at the end of the war. He even started it. The plan was to have hundreds of square miles underground. This is one of the entrances, in a sleepy village in Poland. All of it is in what is now Poland, in the southwest corner. They used concentration camp slaves to build it. This is the nice little entryway.

Because all the workers were killed, this place and the plan weren't even discovered until decades after the war. Here's the entrance to the city. It was called Project Riese.