Krubera Cave (, ; also known as Voronya Cave, sometimes spelled Voronja Cave) is the second-deepest-known cave on Earth, after the Veryovkina Cave. It is located in the Arabika Massif of the Gagra Range of the Western Caucasus, in the Gagra District of Abkhazia, a breakaway region of Georgia. The difference in elevation of the highest cave entrance (Arbaika) 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. Naming Soviet speleologists who explored the cave in the 1960s named it for Russian geographer Alexander Kruber. The alternate name "Voronya Cave", "Crows' Cave" in Russian, was a name given to the cave by Kyiv speleologists during the 1980s, for the crows nesting in the entrance pit. Location and background The Arabika Massif, the home of Krubera (Voronya) Cave, is one of the largest high-mountain limestone karst massifs in the Western Caucasus. It is composed of Lower Cretaceous and Upper Jurassic limestones that dip continuously southwest to the Black Sea and plunge below the modern sea level. To the northwest, north, northeast, and east, Arabika is bordered by the deeply incised canyons of Sandripsh, Kutushara, Gega and Bzyb rivers. The Bzyb River separates Arabika from the adjacent Bzybsky Massif, another outstanding karst area with many deep caves, including the Snezhnaja-Mezhonogo-Iljuzia System () and Pantjukhina Cave (). To the southwest, Arabika borders the Black Sea. The Arabika Massif has a prominent high central sector with elevations above the tree line at ~. This is an area of classical glaciokarstic landscape, with numerous glacial trough valleys and cirques, with ridges and peaks between them. The bottoms of trough valleys and karst fields lie at elevations of , and ridges and peaks rise to . The highest peak is the