Kow Ata (also The Bakharlyn) is an underground lake in an eponymous cave near Bäherden in Turkmenistan, at the foot of the Kopet Dag.[1][2] It is the largest in Commonwealth of Independent States.[3]
The landform was first documented by archaeologists in 1856.[1] Coverage by the local press in 1896—noting the authorities of Bäherden rail-station to have had a wooden staircase installed for safe descent—led to tourists from Ashgabat flocking the site.[1][3]
In 1960s, a road was constructed to the cave, electricity supplied, and hotels built in nearby areas.[3]
The cave has a length of 250 m and variable width of 12–50 m.[2] There are five entrances.[2]
The lake is at a depth of 55 metres (180 ft) from the 3rd (by height) cave entrance;[a] no sunlight reaches the cave.[4][5] Length is reported to lie between 75 metres (246 ft) and 80 metres (260 ft); breadth varies, across the length, between 8 metres (26 ft) and 23 metres (75 ft).[2][3] Average depth is about 10 metres (33 ft); maximum depth is 15 metres (49 ft).[6]
The temperature of the lake remains roughly constant throughout the year, between 33 °C (91 °F) and 38 °C (100 °F).[4] The water has a high mineral content[b] and is especially rich in sulfur.[4] The water is transparent with a shade of bluish green.[5]
Bats, rodents, birds, and about 50 invertebrate species inhabit the cave.[2]
Bathing is permitted in Kow Ata, making it a prominent weekend destination for residents of Ashgabat.[4] A long-winding illuminated staircase leads to the cave.[7][6] Changing cubicles and an observation platform are provided at about 80% length of the stair-route.[8] There are no safety features except a tape warning swimmers to not proceed beyond.[8]
Balneotherapy is practiced.[2]