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".
Martyn Farr
Farr began caving in 1961 and cave diving in 1971, and within 10 years had established a world record for underwater cave penetration in the Bahamas. He is noted within the cave diving community for his explorations in Wookey Hole in 1977 and 1982, and for completing the first traverse of Llangattock Mountain in Wales in 1986, the execution of which was a televised media event, being the longest and deepest caving through trip in the British Isles. In 1978, Farr discovered also the Pollatoomary cave in the Partry Mountains of the Republic of Ireland. In 2008, his student Artur Kozłowski explored this cave to a depth of 103 metres, which made it the deepest known cave on the British Isles.