An example of the encroaching Gobi Desert appears to the south of Dunhuang in the form of enormous sand dunes surrounding a small, crescent moon lake where a small Buddhist temple was built. The Mingsha (singing sands) are celebrated for the sounds they produce alone or when people walk on them. The tallest dune, known as Sha Jiao Mountain during the Eastern Han (25-220), rises to a height of 1,715 meters above the Dang River. For over 2,000 years this extensive line of dunes has spread out over 800 square kilometers into the flat gravel highlands which separate the valley from the Richthofen Range of the Nanshan.
The Chinese have invented a series of myths to explain the phenomenon. One tells of how the area was originally a fertile oasis before a huge battle took place. A sympathetic goddess sprinkled incense ashes over the corpses which were scattered across the desert and a great sand mountain buried the army. From time to time military music can be heard from inside the giant dune. Alternatively there is the tale of the mountain known as Qingshi (Blue Stone). At the foot of the mountain by the crescent moon lake stood a cluster of temples. Operas were held to worship the temple god, but they annoyed the sleeping Yellow Dragon Prince in the nearby desert. One day out of spite he buried the mountain and the people with sand and it is the screams of their souls which visitors can still hear.
The dunes have spread to the cliff where the Mogao Caves are located, and are becoming an increasing threat to the grottoes. Attempts are being made to stabilize the flow of the sand and prevent it from sifting down over the cave facade and eroding everything in its path.