Riese was the code name for a construction project of Nazi Germany between 1943 and 1945. It consisted of seven underground structures in the Owl Mountains and Książ Castle in Lower Silesia, which was then Nazi Germany and is now Poland.

Mittelwerk was a German World War II factory built underground in the Kohnstein to avoid Allied bombing. It used slave labor from the Mittelbau-Dora concentration camp to produce V-2 ballistic missiles, V-1 flying bombs, and other weapons.