Slovenia is a karstic land, and its region of Kras in fact provided the name for all such phenomena in the world, since the experts first analysed these phenomena right there. Every year cavers discover new caves in Slovenia, and to date there are more than 8,000, while just over 20 have been arranged for visitors. The biggest and most popular of these is Postojna Cave, home of the proteus salamander. Many visitors are also enthralled by Škocjan Caves, which are on the world natural and cultural heritage list kept by UNESCO. Snežna jama (Snow Cave) below Mt. Raduha is also a special attraction with its ice stalactites. The shallow-karst caves in Dolenjska are also quite extraordinary.