The karez are a network of underground irrigation channels — vertical wells linked by gently sloping tunnels — that have carried glacial meltwater from the Tianshan Mountains to the Turpan oasis for around two thousand years. By keeping the water underground, the system avoids the catastrophic evaporation losses of an open canal in 45°C desert heat.
The Karez Paradise visitor centre on the northern edge of town lets you descend into a still-functioning channel and walk a short section underground; an attached museum displays maps, tools, and the family histories of the karez diggers. Pleasantly cool even in midsummer. Worth an hour.