The underground city Osówka

At the end of 1943, the Nazis built a military complex in Lower Silesia as a part of Project Riese – the code name for constructing seven underground structures in Lower Silesia. The project's purpose is not clear – some suggest it planned to be a headquarters, while others think it intended to serve the arms industries. Today it is possible to see 1500 meters of underground corridors, halls, and bunkers. The visit is guided, both with a guide and with an audio guide.