Located about 30km northeast of Lhasa, Drak Yerpa is one of the four big propitious places for hermits in Tibet. Built on a hillside at an altitude of 4,885m, it is believed there were 108 caves that used to house about 300 monks in the past, but now only a dozen of them still exist. The remaining caves can be found in the spectacular limestone cliffs of the Yerpa Valley and opposite the main caves lies an ancient sky burial site.