Krubera Cave
The difference in elevation of the cave's entrance and its deepest explored point is . It became the deepest-known cave in the world in 2001 when the expedition of the Ukrainian Speleological Association reached a depth of which exceeded the depth of the previous deepest-known cave, Lamprechtsofen, in the Austrian Alps, by . In 2004, for the first time in the history of speleology, the Ukrainian Speleological Association expedition reached a depth greater than , and explored the cave to . Ukrainian diver Gennadiy Samokhin extended the cave by diving in the terminal sump to 46 metres' depth in 2007 and then to 52 m in 2012, setting successive world records of 2,191 m and 2,197 m, respectively. Krubera is one of the two known caves on Earth deeper than 2,000 metres.
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 .