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.
Bill Steele (cave explorer)
Charles William Steele, Jr. (born October 17, 1948), known as “Bill Steele,” is a cave explorer. He is a speleologist who has led and participated in expeditions to many of the longest and deepest caves in the USA, Mexico, and China. He has explored more than 2,500 caves across North America and Asia and has written two books chronicling his expeditions: "Yochib: The River Cave", and "Huautla: Thirty Years in One of the World's Deepest Caves.” TV shows such as National Geographic Explorer, NOVA and How’d They Do That? have aired programs on his expeditions.