Mati Si is a complex of cave temples carved into a sheer cliff face south of Zhangye, in the Qilian Mountains foothills at about 2,000 metres altitude. The grottoes are connected by tight vertical passages cut through the rock, with ladders and narrow tunnels linking chambers stacked up the cliff at several levels. The interior spaces contain Buddhist statues, painted murals, and carvings in various states of preservation, some dating to the fifth century.
The surrounding valley is also beautiful — a green gorge with the monastery and grottoes appearing almost as an afterthought against the scale of the cliffs. The journey from Zhangye takes about an hour and a half by bus or taxi; a visit works well as a half-day excursion, combining with the grassland scenery of the Qilian foothills on the way. The complex can be cold even in summer — bring a layer.