In numerous places during my trip through Mustang I noticed man-made caves, usually situated in what seemed to be almost completely inaccessible places. On the far side of the spectacular gorge at the edge of Tsarang for example there are 20 or so caves in the cliff hundreds of feet above the ground. It is hard to imagine how these and most of the other caves I saw could have been excavated, let accessed. On the sheer cliff above the bridge at Chele is a line of 16 caves, or more likely square windows for the caves or perhaps a passageway inside. I was so impresses by these caves that I observed them for a while trying to imagine how they could have been reached or why anyone would want to excavate them in such an inaccessible place. The only thing I could imagine is that the walkway that originally led to them has fallen away or eroded away, although I could seen no sign of this. When Giuseppe Tucci was in Mustang in 1952 he too was intrigued by these caves. Locals told him they were cut during the Tibet-Nepal war of 1855-6 as a hiding place for people fleeing from danger, an explanation he considered unlikely (G. Tucci Journey to Mustang, 1977, p.141). He manages to get into one of these caves and found “no objects and no trace of decoration”. Given that all the caves I saw were within walking distance of villages and that Buddhist monks have long favored living in caves, I assume that they were excavated by or for monks. Several accessible caves north of Lo Manthang have functioning monasteries attached to them.
On returning to Singapore I tried to find something on the internet about these mysterious caves and the first thing that came up was a fascinating National Geographic documentary on this very subject. It can be seen at http://www.youtube.com/watch?v=_f5iWG0bRFU