Sun Moon Lake (Chinese: 日月潭; pinyin: Rìyuètán; Wade-Giles: Jih⁴-yüeh⁴-t'an²; Zintun in the Thao language) is the largest natural lake in Taiwan as well as a tourist attraction. Situated in Yuchih, Nantou, the area around the Sun Moon Lake is home to the Thao tribe, one of aboriginal tribes in Taiwan. Sun Moon Lake surrounds a tiny island called Lalu. The east side of the lake looks like a sun and the west side looks like a moon, hence the name.

Sun Moon Lake is located 748 metres (2,450 ft) above sea level. It is 27 metres (89 ft) deep and has a surface area of approximately 7.93 square kilometres (3.06 sq mi).

In older English literature it was commonly referred to as Lake Candidius, after the 17th century Dutch missionary Georgius Candidius. In the middle of the lake is the Lalu Island, which is the holy ground for the Thao tribe. Originally, the Lalu was where the Thao people inhabited. Under the Japanese occupation of Taiwan, the Japanese named it the "Jade Island". After Chiang Kai-shek's Nationalist Government moved to Taiwan, the island was renamed Kuang Hua ("Glorious China") and in 1978 the local government built a pavilion where annual weddings took place. The 921 Earthquake destroyed the pavilion and sunk most of the island. In recent years, due to increasing social and political awareness, more deference and recognition are being given to Taiwanese aborigines. As a result, after 921 earthquake, the island was renamed in the Thao language as "Lalu".[1]