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".
Jarrod Jablonski
Jablonski has been setting records for cave penetration for many years. In 1995 he and Geologist Todd Kincaid pushed the Manatee Springs cave system to . On April 25, 1997, Jablonski along with George Irvine and Brent Scarabin set a new penetration record of in Wakulla Springs. They utilized Halcyon semi-closed circuit rebreathers at an average depth of . In July 1998 Jablonski, again diving with Irvine and Scarabin traveled in Wakulla Springs O-Tunnel. Jablonski and his regular dive buddy WKPP director Casey McKinlay set a world record for the longest ever penetration on a cave dive, at while exploring "Q" tunnel of Wakulla Springs.
This record remains the longest penetration in a deep cave. The new record for the longest penetration at any depth is now held by Jon Bernot and Charlie Roberson of Gainesville, Florida, with a distance of .