Due to the hot and dry weather conditions, the region's evaporation rate is 140 times more than its precipitation. As a result, salt from the lake's surface is gradually crystallized and a solid salt cover of 1-4 meters thick is formed. This cover is extremely hard and heavy.

The vast and flat geological conditions have contributed to the area's unique and spectacular landscape. The lake's surface looks like arable land that has just been ploughed. On a sunny day, the lake emits a light steam, resembling an ocean. A mirage can appear on some occasions, adding glamor to the natural wonder.

The Cha'erhan Lake was the last to be explored among the four great Qaidam salt lakes. In the 1950s, the "Salt Bridge" was built on the solid lake cover. The first settlers built roadbeds, repaired holes and finally completed the 32-kilometer-long bridge without using any steel, wood or stone. The largest potassium fertilizer factory in China was also erected on the Cha'erhan Lake.

 Qaidam Basin -- One of the Four Greats

The Qaidam Basin, one of four great Chinese basins, is located in the deep Qinghai-Tibet Plateau, encircled by Arjin, Qilian and Kunlun mountains. With an average altitude of 4,000 meters, Qaidam boasts more than 5,000 salt lakes.

Qaidam, known as a mysterious treasure trove, was once an important passage between the East and West. In the southwest of the basin stands Kunlun Mountain -- the cradle of the famous Kunlun Taoist myths. According to an ancient legend, an emperor from the Zhou Dynasty (1100-221BC) once met Xi Wang Mu (Queen Mother of the West, a legendary figure of Taoist mythology) in Qaidam. In the Northern and Southern dynasties (420-581), Qaidam was once a thriving passage for the Silk Road and a large number of coins and textiles from the Persian Kingdom and other states in the western regions have been excavated there.