Bakharden Underground Lake

The Bakharden Underground Lake — Köw Ata — in Turkmenistan's Ahal region is one of the world's most extraordinary underground thermal experiences: a warm sulphurous lake of remarkable size, 65 metres long and up to 8 metres deep, lying in a vast natural cave 65 metres beneath the Kopet Dag mountains, accessible by a 65-metre descending tunnel, where the ambient temperature remains at 33–37°C and the sulphurous water fills the lake to a consistent therapeutic warmth. The cave is inhabited by enormous bat colonies that roost in the limestone ceiling — hundreds of thousands of individuals that have colonised the warm cave environment — and the combination of underground lake, stalactites, warm sulphurous water and bat spectacle creates an experience genuinely unlike any other thermal bathing in the world. Turkmenistan's austere desert landscapes of the Karakum and the remarkable UNESCO-listed ancient cities of Merv and Nisa provide a broader context of considerable historical interest.