The deepest in Russia. The depth of the cave reaches more than 900 meters, and the length is 3 kilometers. Starting from a depth of 170 meters, the cave is quite heavily flooded, which leads to frequent collapses. Scientists have reason to believe that the true depth of the cave is much greater, but it was only discovered in 1994.

In terms of sports and technology, the karst cave is very difficult, so only speleologists with special skills can move through it. The descent is a narrow well, through which a cold stream constantly flows. Below 170 m, in the depths of the cave, there is strong humidity, which leads to frequent collapses. Inside there are many beautiful stalactites, stalagmites, underground rivers and lakes.

It is named after one of the heroes of Tolkien’s epic “The Lord of the Rings”. You can get into the cave only with the help of special climbing equipment. Inside, visitors are greeted by an abyss called the Grey Troll: a vertical cliff 160 meters deep. It is quite cold inside and there are flooded areas, so a wetsuit is needed to pass through. In addition to stalactites and stalagmites, researchers have discovered large deposits of transparent calcite in this cave. This mineral was used in ancient times to create the first stone structures.