The Pa-O are the seventh largest ethnic nationality in the Republic of the Union of Myanmar. They are the second largest ethnic group in the Shan State, and also live in Kayin State, Kayah State, Mon State and Bago Division. They are believed to be of Tibeto-Burman stock, and are ethnolinguistically related to the Karen. The Shwe Indein Pagoda is a collection of Buddhist stupas dating back to the 16th and 17th centuries CE. Inle Lake is a freshwater lake located in the Nyaungshwe Township of Taunggyi District of Shan State, part of Shan Hills in Myanmar (Burma). It is the second largest lake in Myanmar with an estimated surface area of 44.9 square miles (116 km2), and one of the highest at an altitude of 2,900 feet (880 m). The people of Inle Lake (called Intha), some 70,000 of them, live in four cities bordering the lake, in numerous small villages along the lake's shores, and on the lake itself. The entire lake area is in Nyaung Shwe township. The population consists predominantly of