Velebit
There are hundreds of "holes" on Velebit. It has the largest and deepest caves in Croatia. The three-part "Lukina jama" cave is 1392 m deep, making it one of the deepest caves in the world, and the deepest in southeast Europe, while the "Slovačka jama" is 1320 m. What makes it unique is that it is completely vertical, steepest in the world. At the bottom of the pothole is a water course or siphon with branches that are still unexplored. A kind of leech was discovered in the pothole, which has been ascertained to represent a new species, genus and family; it has been named "Erpobdella mestrovi".
Kinderle Cave
The entrance to the cave is located at an altitude of 94 m and is connected to an inclined tunnel. In the tunnel is a glacier measuring 720 square m and a thickness of 8 m. Various stalagmites grow on the glacier. The length of the cave is 8130 m, including 230 m under water. The volume of the cave is 229600 cubic meters, the floor area is 39400 square meters. The average width of the pass is 5.4 m, the height is 7.1 m. The amplitude of the corridors is 215 m, this is the deepest cave in the Urals. Around the cave grows cannabis, so the Bashkirs called the cave Kinderle. They kept meat on the glacier in the summer.