Vjetrenica

Vjetrenica (Serbian Cyrillic: Вјетреница, pronounced [ʋjɛtrɛ̌nitsa]; lit. 'wind cave' or 'blowhole') is the largest cave in Bosnia and Herzegovina, and the most biodiverse cave in the world. It is part of the Dinaric Alps mountain range, which is known for its karstic and speleological features. The cave is located in the Popovo field in Ravno, East Herzegovina in the Federation of Bosnia and Herzegovina.

Source: Wikipedia (CC BY-SA 4.0) — https://en.wikipedia.org/wiki/Vjetrenica_Cave