Today, the Irkutsk cave is considered the longest in Russia. The underground labyrinths in the Angara region have been explored for almost 100 years, and speleologists have already explored more than 70 km of branching passages. Underground cavities in limestone and sandstone were formed about 1.5 million years ago. In 2019, a speleological expedition discovered skeletons of prehistoric bears in a remote part of the cave, the age of which exceeds 700 thousand years. Researchers divide the unique dungeon in the depths of the mountain range in two: the “Old World” with a system of narrow tunnels in which it is easy to get lost, and the “New World”, where you can walk at full height. Botovskaya Cave is open to tourists, but the road to it takes a lot of time and effort. There are six entrances to the cave system, all of them are located in a dense forest, so it is better to go with a guide.