Aydingkol, whose name means moonlight lake in Uyghur, sits in the Turpan Depression about forty kilometres south-west of Turpan city, and its shore is 154 metres below sea level. That makes it the lowest point in China and one of the lowest land surfaces on earth. The depression itself is a fault-bounded basin between the Tianshan ranges, and it works as a sump: the snowmelt rivers and the underground channels of the karez system lead water into the middle of the basin, where there is nowhere for it to go but up into the air.
Why the lake is disappearing
Because the basin has no outlet, everything dissolved in the water it receives stays behind. The lake was once a shallow brackish sheet; as more of the inflow has been drawn off upstream for irrigation in recent decades, less reaches the middle, and what remains is a wide, flat crust of salt and mineral deposits with ponds of brine around the edge and dry, cracked polygons in between. Salt-tolerant plants - glasswort and other halophytes - grow in the fringes, and the crust is bright white, which is what makes the site so striking under a strong sun.
What it is like to visit
The effect is strongest in summer, when the heat over the salt flat produces mirages: sheets of apparent water that recede as you approach them, and distorted shapes on the horizon. The horizon itself is low and the surrounding hills bare, so the sense of being at the bottom of a bowl is easy to feel. There is a boardwalk and a marker recording the elevation, and the flat extends much further than the marked area, but the crust is soft in places and walking far out is not advisable without a local guide.
Practical notes
There is no public transport; go by car, which takes about an hour from Turpan. Summer temperatures in the basin are extreme and the ground radiates heat, so a hat, water and sun protection are essential, and the middle of the day is best avoided in July and August. The site combines naturally with the karez wells and the old city, which are on the same side of Turpan, and with the vineyards of the surrounding villages.
