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.

Książ Castle is a castle in northern Wałbrzych in Lower Silesian Voivodeship, Poland. The largest castle in the region of Silesia, it is the third-largest in Poland behind Malbork Castle and Wawel Castle. It lies within Książ Landscape Park, a protected area located in the Sudetes and Sudeten Foreland. The castle overlooks the gorge of the Pełcznica river and is one of Wałbrzych's main tourist attractions.