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.
Tears of the Turtle Cave
The entrance to Tears of the Turtle Cave was found in 2006. The cave passage is mostly a two to three foot wide fissure that follows a stream downward through numerous rappels. In 2014 a team of nine cavers explored new passage pushing the cave to a depth of 1629 feet and in doing so passed New Mexico's Lechuguilla Cave to become the deepest known limestone cave in the United States. Exploration continued in 2016 when teams returned to push the cave to its current known depth of 1659 feet. On those trips the difficulty necessitated establishing camp in the cave for the first time. This, along with the technical rope work, 39 degree temperature, and remote location of the cave make continued exploration difficult. A return trip is currently planned for 2019.