One of the most interesting stops on the Turpan tour is Karez Wells. It's the site the locals are most proud of, and rightfully so the irrigation method is probably their greatest contribution to desert dwellers and has been employed as far away as Afghanistan and Iran. More than 2,000 years ago, it was developed as a way to bring the snowmelt waters of the Tian Shan to the city through a series of wells dug into underground water channels. By transporting the water underground, they were able to prevent evaporation and to keep dust and dirt out of their water supply. The Karez Wells is like a museum explaining how the wells are built and maintained and even includes a sample channel and well that you can explore.