the four great caves, namely: Longmen Grottoes 龍門石窟|龙门石窟[Long2 men2 Shi2 ku1] at Luoyang, Henan, Yungang Caves 雲岡石窟|云冈石窟[Yun2 gang1 Shi2 ku1] at Datong, Shanxi, Mogao Caves 莫高窟[Mo4 gao1 ku1] at Dunhuang, Gansu, and Mt Maiji Caves 麥積山石窟|麦积山石窟[Mai4 ji1 Shan1 Shi2 ku1] at Tianshui, Gansu