Under Predjama Castle, above and behind it, there is an interesting intertwining of karst caves.
The most important of them is the cave under Predjama Castle, which is the second longest tourist cave in Slovenia, and extends over four floors – except for the uppermost Erazem’s hole with the tunnel, they are all connected to each other.
The length of all parts of the cave discovered so far is 14 kilometers. The tourist section measures 700 meters and includes the Horse Stable, the Main Tunnel, the Name Tunnel, the Great Hall and Fiženca, where there is an exit to the surface.
Archaeological finds in the cave behind Predjama Castle testify that people already lived here in the Stone Age. Remains from Roman times were found in the entrance tunnel of the cave, called the Horse Stable, and signatures from the 16th century are on display in the Name Tunnel.
You can see a part of the cave as part of the castle tour, and the rest as part of the adventure experience. The cave does not have electric lightning, and visitors are given flashlights before entering. To see the tourist section, only comfortable clothing and footwear is required. Due to its location and favorable temperature, the cave hosts a colony of bats in the winter, so it is closed to visitors during their hibernation.
The Cave under Predjama Castle is open to visitors from May to September.