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.
Krubera Cave
The biocenosis of Krubera-Voronja is composed of more than 12 species of arthropods of several groups, such as pseudoscorpions, spiders, opiliones, crustaceans, springtails, beetles and dipterans. Krubera-Voronja cave is inhabited by endemic species, including four springtails discovered during the CAVEX Team expedition of 2010: "Anurida stereoodorata", "Deuteraphorura kruberaensis", " Schaefferia profundissima", and "Plutomurus ortobalaganensis"; the last of these is the deepest terrestrial animal ever found on Earth, living below the cave entrance. The beetle "Catops cavicis" inhabits Krubera-Voronja cave and also several caves around the Ortobalagan valley. The subterranean amphipod crustacean "Kruberia abchasica" caught by Gennady Samokhin in August 2013, during dives in the siphon 'Dva Kapitana', dwells at the deepest part of the Krubera Cave (at the depth of -2,175 metres).