Karez water system (video)

Many many years ago (more than 20, actually), I went on a trip along the Silk Road. One of the places visited was Turpan, where we saw the karez water system which supplies water to this city in the middle of a desert.

So when I saw this video, I just thought I would share it for more people to learn about this interesting water system, an ingenious way of dealing with the issue of water in a desert.