World`s greatest Orda Cave

Orda's Cave  Lyagushkin Viktor (Viktor Lyagushkin) did an amazing and rare photos of underwater caves Orda, the second largest cave in the world.
Orda cave located on the eastern outskirts of the village Horde Perm region, on the left bank of the river Kungur. Consists of "dry" and the underwater part. The length of the dry part is 300 meters underwater - 4200 meters. To date, Orda Cave is the longest flooded cave in Russia. In addition, part of the cave is the longest siphon in the CIS - 935 meters, as Wikipedia tells us.