Construction of the Dujiangyan irrigation system began in the 3rd century B.C. This system still controls the waters of the Minjiang River and distributes it to the fertile farmland of the Chengdu plains. Mount Qingcheng was the birthplace of Taoism, which is celebrated in a series of ancient temples.
Since 2000 it is a Unesco site.
Thanks to Cindorchen for the postcard.