The Baradla Cave System is the Hungarian part of the 25-kilometre-long Baradla-Domica Cave System, the largest subterranean hydrological system of the karst plateau in Hungary and Slovakia. The Site is characterized by a permanent subterranean stream, ponds, rich dripstone formations, and diverse species representative of subsurface fauna as well as rich archaeological remains. The extensive underground world of the Aggtelek and Slovak Karst regions provides a habitat for more than 500 species of troglobite, troglophile and trogloxene animals, including endemic species such as the beetle Duvalius hungaricus and earthworm Allolobophora mozsaryorum. The Site also includes habitats of community interest such as wet meadows and humid grasslands. The sediment of the cave system plays an important role in the filtration of heavy metal pollution. Of archaeological importance are the settlements of Bükk culture both inside and in front of the cave entrance, with charcoal drawings unique in Central Europe. More than 100,000 tourists visit the Site annually, for whom tours and study trails, as well as hotels and campsites, are available. Threats relate to forestry and pollution from wastewater and domestic waste.