Velebit caves
The "Lukina jama" cave is 1431 m deep (2013), the deepest cave in Croatia, 14th deepest cave in the world and the deepest cave in southeast Europe. At its foot, there are ponds and streams including one of the largest known colonies of subterranean leeches ("Erpobdella mestrovi"), which has been ascertained to represent a new species, genus and also family. Other species discovered in the system, include the air-breathing land snails "Zospeum tholussum". Like Lukina jama, Slovacka jama, Velebita and Meduza are also located at the "Hajdučki i Rožanski kukovi" special reserve, a dedicated part of the Sjeverni Velebit national park.
Nettlebed Cave
Until April 2010, when the nearby Ellis Basin cave system was found to be deeper, Nettlebed Cave was thought to be the deepest cave system in the southern hemisphere. It drops 889 metres below its upper entrance (Blizzard Pot) to its lower exit (the Pearse River resurgence), and its 24 kilometres of cave passages make it New Zealand's third longest cave.