Vjetrenica is the biggest and largest cave in Bosnia and Herzegovina, known for its caving wealth, and it is located close to the village Zavala (Popovo polje). There are 6 300 m of underground channels and the main one is 2 047 m.

Geologists assume that Vjetrenica could extend all the way to the Adriatic Sea, which is 15-20 kilometres length. Potholing features of this cave are large halls, chamber, sedimentations of stalactites and stalagmites, many lakes, few waterfalls, number of streams, and also often fog in the parts of “Absolon channel”. It has rich cave′ s world with almost 200 different animal species, of which 91 troglobionate and 37 of them were found and described on this place, which makes this cave one of its kind according to bio-differences. The cave is rich with endemic species and the most famous one is Proteus Anguinus, which is very sensitive to changes of light, temperature and noise.

Vjetrenica was described for the first time in Plinius Older in his work “Historia Naturalis” from 77 of this era. Czech K. Absolon made the biggest researching in the beginning of the 20th century. There were many interesting findings in Vjetrenica, among which leopard′ s skeleton stands out (found in 1968), and more partial remains of animals.