Šupljara cave is located along the northern edge of the Lower Lakes in a limestone canyon slopes above the lake Kaludjerovac. It is possible to pass through the cave. It was water seepage through the fractured surface, which is a solvent limestone rock. Here are the expanded underground cracks and create channels. Groove canyons of the Lower Lakes and increasing underground cavities beneath a sinkhole located on the edge of the canyon, have led to instability and collapse of the bottom of sinkholes, caves, or vault. The open access to hidden areas and passing by the lake today Kaludjerovac.