Special supplement: Ancient water wonder nurtures nation

If the all ancient Seven Wonders of the World still existed today, one would clearly see that they were man-made.

Yet there is a wonder in China that looks as though it was formed by nature, though it too was man-made. It has been bringing enormous benefit to millions of people over 2,200 years, but you can hardly notice the human touch.

The Dujiangyan irrigation system, largely responsible for the prosperity in the Chengdu Plain, "has perpetually irrigated the Chinese nation", said Yu Qiuyu, influential writer and interpreter of China's landmarks.