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".
Quri Qala Cave
Quri Qale Cave or QuraQala (Kurdish: Şkefta QureQela, ئەشکەوتی قوڕەقەڵا Persian: غار قوری قلعه) is a cave located northwest of Ravansar, Iran, and is one of the longest caves in western Asia. First explored in the 1950s, in 1989 it was further opened by an Iranian team. It contains three main chambers, with calcite crystals, stalactites and waterfalls. It is known for its colony of mouse ear bats, and for a number of archaeological finds, including silver plates dating the late Sassanian period.