Karez Irrigation System was created by ancient Uygur people at the second half of 18th century. It can mainly be found in the area of Turpan, Hami and Helei. If connecting all these underground channels together, the total length will reach more than 5000 km, so it is regarded as one of ancient China's greatest public projects.
Karez reduces evaporation, avoids getting polluted and needs no other power equipment. Turban is the hottest place in China and the arid climate makes water all the more precious. A karez system helps to ideally solve this problem. Karez also functions as the natural air conditioner for the locals when they sit nearby, chatting or taking a rest.