Kow-Ata Underground Lake

Most caves demand a jacket. Kow-Ata Underground Lake, in the Kopet Dag foothills near the town of Bakharden approximately 90-100 km west of Ashgabat, demands a swimsuit. The cave shelters a large underground lake open to swimmers, and the water - warmed by geothermal heat to around 33-37°C (91-99°F) year-round - sits in a cavern of cathedral scale, dimly lit and laced with the sharp smell of hydrogen sulfide.

The name translates from Turkmen roughly as "Father of Caves" or "Father Cave" - "kow" relating to cave or hollow, and "ata" meaning father. It has been known for centuries, valued for the supposed therapeutic properties of its mineral-rich water. The descent into the cave follows a long staircase down through the rock, the temperature rising and the light fading as you go, until the cavern opens up and the lake appears below - dark, steaming faintly, improbably large.

Swimming in Kow-Ata is a peculiar and quietly wonderful experience. The water is buoyant and warm, the ceiling of the cave arches overhead in the dark, and the whole scene feels genuinely otherworldly - not in the marketing-brochure sense, but in the literal sense that nothing about it resembles anywhere else. Minerals dissolved from the surrounding rock give the water a faint opacity. Bats use the upper reaches of the cavern. Outside, it might be midwinter with snow on the Kopet Dag peaks; inside, it is always the same warm, mineral-scented dark.

What surprises most visitors is the sheer size of the space. The cave is enormous. The lake extends well beyond the lit swimming area, disappearing into darkness in a way that gently reminds you that you are, in fact, underground in a mountain.

It is worth noting that Kow-Ata is not a spa or a wellness resort - it is a cave with a lake in it, which is considerably more interesting.