Tsetang, in the fertile Yarlung Valley 183 kilometers (113 miles) southeast of Lhasa, is considered the "cradle of Tibetan civilization." According to legend, it was in a cave here that a monkey emanation of Avalokiteshvara (Bodhisattva of Compassion) mated with an ogress, thereby giving birth to the original Tibetan clans. Perched on a craggy ridge in the vicinity of this legendary cave, overlooking the first cultivated fields in Tibet, is the resplendent Yumbu Lagang palace. Legend has it that sacred texts miraculously fell on the palace roof, heralding the first appearance of Buddhism in Tibet.