Dunhuan Mogao Cave is the largest and best-preserved historical Buddhist site in the world. But why were such great works of art set up on a cliff in the desert in China's northwest. It is said this site was chosen by a monk. In 366, Le Zun traveled to Sanweishan Mountain in Dunhuang. The sun was setting, but he couldn't find any place to live in. While he was pondering his predicament, he looked up at the sky and was dazzled by golden rays from nearby Wusha Mountain. It seems that tens of thousands of Buddhists appeared. Bewildered by the grand scenery, Monk Le Zun assumed that this was a sacred place, so he hired craftsman to carve grottoes. In the Tang Dynasty, the number of these grottoes had surpassed 1,000.