Located in village Kletno, in the Stroma hill, Jaskinia Niedźwiedzia (“Bear Cave”) is the longest cave in the Sudetes. The corridors have the joint length of over 4 km and have developed on three levels. Inside there are numerous cave formations counted among most interesting in Polish caves. Radioactive gas radon has been found in the cave.
The cave's name comes from bear remains discovered inside. The Bear Cave is situated within nature reserve Jaskinia Niedźwiedzia (89 ha). The middle region of the cave (about 700 m) is made available to tourists.