The iconic Tianqiao (or Heaven's Bridge) site is comprised of a series of Daoist temples built into successive narrow ridges inside a concave section of the cliff wall. The 300-meter-long plank walkway that hangs 80 meters above the road was originally built over 1000 year ago. Tianqiao was also the site of an important military stronghold in the late 3rd and early 4th centuries A.D.