Krubera Cave in the Caucasus Mountains in Georgia is one of the most dangerous caves in the world to explore. This cave, which lies in the region of Abkhazia, has seen divers and spelunkers explore up to a depth of as much as 1.3 mi (2,091 meters). Still, they haven’t found the other end of it! What’s more, the cave also travels for as long as 10 miles under the mountains.Krubera is also famous as one of the oldest known caves in the world. It predates even the Jurassic period, and geologists believe that it was carved out due to prehistoric ﬂooding.