Aktash sinkhole

The sinkhole in Kaleikino village, Russia, is a popular diving spot for expert divers. It is situated on the edge of the village, with a diameter of approximately 50 meters and a depth of 25 meters. The sinkhole offers a silted entrance to a cavern on its north side.
Periodically, juveniles of freshwater fish species are introduced into the sinkhole. However, due to limited illumination and food supply, a stable reproducing population is not established.
Divers visiting this site should note that there is no dedicated infrastructure for diving equipment, cylinder filling, or equipment rental. Accommodation can be arranged by renting a house in the village or setting up a tent. Access to the sinkhole is through steep free-flowing slopes, requiring divers to wear their equipment in the water.
Important details about the site include a visibility of 4 meters and a maximum depth of 27 meters. It is recommended for expert divers. The sinkhole is located near the "Aktash Failure," which is the deepest lake in Tatarstan, Russia.