In 1937 a rapid increase of the subterranean water fractured the rock and opened a natural entrance for the people of surrounding villages. In 1971 lightning installation was made and 300m of main attractions were offered to tourists. The length of the cave is a bit more than 2 kilometres but cavers are still exploring the entire cave system.

The footpaths in the cave are suitable for children as well as older visitors. A guided tour with explanation lasts 40 minutes. The constant temperature in the cave is 12 degrees Celsius.
Kostanjevica Cave lies at the foot of the Gorjanci hills, a diverse karst terrain with cretaceous limestone. Rain water, subterranean watercourses and tectonic movements spent millennia creating dreamlike cave formations with fairytale motives.