Among the high snow-covered spines of the Tien-Shan is a picturesque mountain lake Issyk-Kul. In translation from the Kyrgyz language Issyk-Kul means "warm lake". And indeed, Issyk-Kul never freezes, even in severe frosts. However, it is hardly possible to consider this name as successful: the water in the Issyk-Kul lake is very cold.

Among the high snow-covered spines of the Tien-Shan is a picturesque mountain lake Issyk-Kul

What is the reason not to freeze Issyk-Kul Lake? For a long time it was believed that numerous hot springs work at the bottom of the lake. However, during the research they were not found. And scientists still found out the reason for not freezing the lake.

The fact is that, through the great depth of the Issyk-Kul Lake (over 700 m), the mass of water in it, heated in summer by hot rays, cools very slowly. And in addition, the water of Issyk-Kul is slightly salted. Strong winds in the winter mix its upper layers and prevent the lake from freezing.

All this misled those researchers who once gave the name Issyk-Kul to the mountain lake. It is interesting that the area of Lake Issyk-Kul is 10 times smaller than the area of the Aral Sea, and there are twice more water in it.

The Issyk-Kul Lake is inundated, with up to 80 relatively small tributaries flowing into it. Of these, the largest are Tyup and Djergalan. In the western part, the Chu River very close to the lake, which along the channel of Kutemaldy, 6 km in length, sometimes gives him a part of its waters during the spring floods. The water level in Issyk-Kul varies cyclically; the cycle takes place over several decades.

The first mention of Issyk-Kul is found in the Chinese chronicles of the end of the 2nd century BC, where it is called Je-Hai, which means "warm sea". However, the scientific study of the lake began only in the 19th century by Russian scientists, including NM Przhevalsky, who was bequeathed to bury himself on the shore of Lake Issyk-Kul.

There are a number of legends about the flooded cities and treasures in the Issyk-Kul lake. Most of them are based on real facts. As shown by underwater excavations, in the coastal zone of the lake there is indeed a number of medieval cities flooded at a later time, including the capital of Usuns Chigu.