Most of the Tajikistan’s lakes (80%) has the surface area less 1 km2. Generally they have tectonic and moraine (glacial) origin. The total number of lakes exceeds 1300, while most (80%) of them are situated on an altitude exceeding 3000 m above sea level. The largest natural lake is Caracul lake with salty water, the surface area is about 380 km2. From the height of bird’s flight the water of the lake seems absolutely black. The name of the lake - Caracul - is translated as “black lake”. The deepest and the most dangerous lake is Sarezskoe lake which volume is approximately equal to 18.9 km3, and depth exceeds the mark of 450 m. Sarezskoe lake arose in February, 1911. The mass of rocks, situated on the right rocky bank of Murgab river opposite village Sarez, alighted down from the height more than 750 meters above earth surface as a result of the powerful earthquake, and covered village Sarez. The volume of the dam of Sarezskoe lake exceeded 2.9 bn. m3. At present the horizon of lake is 40 meters below the minimal mark of the surface of the dam. Water horizon periodically fluctuates attaining 10-12 meters. Within winter period the lake is covered with ice, but during summer period the water temperature on the depth of 30 cm does not exceed +12C. Flowing through the obstruction the water of the lake is filtered. Generally, dam is rather a stable structure: its transversal profile is quite reliable because the ratio of its basement's breadth to the depth of lake is rather big. The breadth of the basement of the dam more than 10 times exceeds the lake depth and its breadth at the level of the water’s horizon 2 times exceeds the depth of the lake. The right side of the dum causes significant apprehension. A several dozens of kilometers due to the south is situated the Yashilkul lake. Although this lake has the similar origin as Sarezskoe lake, it was formed in prehistoric times and the condition of dam does not cause any apprehensions because this lake is considerably smaller than lake Sarezskoe as well as dum has much firmer structure than the dum of lake Sarezskoe. In Tadjik part of Fergan valley (Northern Tajikistan) there is lake Oxukon with a dirt, known for its medical properties. Lake Oxukon is 8 km long. The maximal depth is 50-70 cm, below which there is a stratum of dirt and silt having salutary properties. Many legends about Alexandr Great are connected with the lake Iskanderkul (Central Tajikistan). According to these legends, his horse Butsefal sank in Iskanderkul lake. Its depth does not now exceed 80 meters. The surface area is 3.2 km2. At the altitude about 30 meters above water horizon one can distinctly see the mark of the primary water level of the lake. Lake enters into the complex of nature refuge (zakaznik) Iskanderkul. In several kilometers to the west there is a complex of Marguzor lakes. Marguzor lakes have moraine origin and are situated in picturesque places. The largest alpine lake of the republic is considered to be Zorkul lake. It is situated at the altitude of 4126 meters above sea level. The surface area of the lake exceeds 35 km2. This is the alone place in Tajikistan populated by the colony of alpine gooses. That is why the lake enters into the complex of nature refuge (zakaznik) Zorkul . Zorkul is the source of river Panji, which merging with the river Vakhsh forms the major aquatic artery of the Central Asia - river Amudaria. The total surface area of all lakes of the country is approximately 690 km2.