Southwest of the Potala, a road leads around the eastern side of Chagpo Ri, the hill that faces Marpo Ri, site of the Potala. Take this road past stone carvers and rock paintings to unmarked steps leading up to the Drubthub Nunnery. The small but friendly nunnery is dedicated to Thangtong Gyalpo, the 15th-century bridge maker, medic and inventor of Tibetan opera, who established the original nunnery on the top of Chagpo Ri. Gyelpo’s white-haired statue graces the nunnery’s main hall.