Its main entrance, 72 m tall, is the largest of all caves on the Balkans. Apart from the main, upper entrance for tourists, there is a smaller, lower entrance into an underground lake, which overflows in rainy seasons, creating an intermittent water flow called Petnica, flowing into Đetinja river. The upper hall has lightened tourist trail, 555 m long, reachable by a staircase of over 700 stairs.