This is Lake Crescent near Dunhuang, in Gansu Province, China.The history of the city dates back to the Han Dynasty. The oasis, which is believed to have existed for 2,000 years, was shrinking fast due to increasing desertification in the region before the government began to refill it.
According to measurements made in 1990 the average depth of the lake is just around 1 meter (in 1960 it was around 4-5 meters). In 2006, the local government started to fill the lake and restore its depth; its depth and size have been growing yearly since then. The Crescent Lake is very popular among tourists.