On the border with the municipality of Kostel, on the left bank of the Kolpa river lie the Bilpa karst cave. They are 20m away from the road. Above the source of the Bilpa river are three karst caves, whish were not discovered until 1941, however, later, in 1983 a fourth cave was uncovered, which is today the most famous.
Valvasor had already written about it, exposing the Bilparska wall, which is in the shape of a human and devil's head - naming it the Wall of Echoes. It is possible to find 20 different human and animal images in the cave altough it is still full of mysteries.
The underground world of the Bilpa is comprised of tunnels on several floors; the lower is expansive and still very active. The entrance to the cave is in the wall, 30m above the ground. It is 8m wide and 6m high.