Karez is a unique irrigation system mainly distributed in Turpan district in Xinjiang Uighur Autonomous Region. It is reputed as one of the three major construction projects in ancient China, together with the Great Wall and the Grand Canal. The history of it can be traced back over more than 2,000 years ago.

On the foothill of hills, snow-water is reserved in small aquifers. A horizontal underground tunnel is dug from the foothill aquifer to village areas. Its length is sometimes 20km long. For regular maintenance purpose, vertical holes are dug every 15m or so that connects the underground tunnel with the field surface. Karez is a system of this underground tunnel and these vertical holes.

The karez skillfully makes use of the geological conditions in the Turpan Basin, radiation from the sun and the atmosphere's circumfluence to form a fascinating agricultural landscape. You can see the performance of the irrigation to find out the intelligence and diligence of Chinese people thousands of years ago.