Van Lake is the largest lake in Turkey and the Armenian Highlands. It lies in the far east of Turkey, in the provinces of Van and Bitlis. It is a saline soda lake, receiving water from many small streams that descend from the surrounding mountains. It is one of the world's few endorheic lakes (a lake having no outlet) of greater size than 3,000 square kilometres (1,200 sq mi) and has 38% of the country's surface water (including rivers). 

A volcanic eruption blocked its original outlet in prehistoric times. It is situated at 1,640 m (5,380 ft). Despite the high altitude and winter highs below 0 °C (32 °F), high salinity mainly prevents it from freezing at such times. Specifically, the shallow northern section can freeze, but rarely.

Van Lake is primarily a tectonic lake, formed more than 600,000 years ago by the gradual subsidence of a large block of the earth's crust due to movement on several major faults that run through this portion of Eastern Anatolia. 

- Wikipedia