The Krubera cave is located in the Arabika Massif on the edge of the Black Sea in Abkhazia, which is a disputed territory bordering Georgia .
Extends for 8.346miles (13.432km) and since 1956 when French explorers first descended below 3,281ft (1km) cavers have tried to get deeper.
In 2007, a Ukrainian diver called Gennadiv Samokhin extended the map of the abyss by diving in ‘the terminal sump’
Krubera Cave is a 16,058 meters long cave system which for most part consists of deep, vertical wells which are interconnected with passages. The cave starts high in the mountains, at an altitude of 2,256 meters, with a narrow entrance. Krubera Cave often is very narrow and had to be carved at many places to allow safe passage. At other places, the passageway is as large as subway tunnel