Drežnička Gradina is a mountain in western Serbia, between cities of Požega and Užice. Its highest peak, Gradina, has an elevation of 932m above sea level. On the cone-shaped hilltop, there is a small stone-built pyramid erected as monument to Yugoslav Partisans died in a battle against German forces in August 1941, at the time of the Republic of Užice.A prominent feature on the mountain is the cave Potpećka pećina, located near the village of Potpeće. 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. The hall with stalactites and stalagmites is still geologically active, and is protected from outer atmosphere by an iron gate.External links Potpećka pećina, web site dedicated to the cave