Planina Cave

Planina Cave, formerly also Little Castle Cave after Little Castle in the vicinity of its entrance, is one of the longest Slovenian active caves. It is a huge tunnel and the subterranean bed of the Unica River. It is located in Inner Carniola. Five hundred meters from the entrance into the cave is a confluence of two underground rivers: the Pivka River, flowing from the Postojna Polje through Postojna Cave, and the Rak River, flowing to Planina Cave through Weaver Cave from Rak Škocjan. This is one of the largest confluences of subterranean rivers in Europe.