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.
Levan Maruashvili
Levan Iosifovich Maruashvili ( born 25 October 1912, Novocherkassk, Russian Empire, — 5 December 1992, Tbilisi, Georgia) was a prominent Georgian geographer. Doctor of Geographical Sciences (1954), professor (1965). Honored Scientist of the Georgian SSR (1966) and Abkhaz ASSR. Honorary member of the Russian Geographical Society (1985). He introduced a new concept of karst-sphere into the science. Krubera Cave, which is the world’s deepest known cave (2197 m), was discovered by the Georgian researchers in 1960 by the leadership of Professor Levan Maruashvili.