Namtso, whose Tibetan meaning is "heavenly lake", is located in the north of Tibet, between the Dangxiong County and the Bange County. The surface of the lake is 4718 above sea level. With over 70-kilometers length from east to west and over 30-kilometers width from north to south, the lake covers an area of over 1900 square kilometers. It's the second largest lagon in China and the highest one in the world. The innermost depth is over 33 meters. The water of Namtso is supplied by thawed ice and snow from Nyainqntanglha Mountain. Along the lake, there are many streams flowing into it. The water is clean, transparent and sky blue. Namtso is crowned as the head of the three saint lakes in Tibet and a famous pilgrimage place for Tibetan Buddhism. There is Zaxi Temple on the Zaxi Island which is in the center of the lake. It is the place pilgrim must worship.