Salt Lake Baskunchak, Russia

The surface elevation of the lake is 21 m below sea level. It is fed by a river that draws from an area of 11,000 km². The salinity of the lake is about 300 g/l. Since the 8th century its salt was mined and distributed via the Silk Road. Nowadays the lake's salt of distinct purity (99.8 % NaCl) covers 80 % of Russia's salt production. Depending on need, about 1.5 million to 5 million tons of salt are mined per year.
To the south of the lake Mount Bolshoye Bogdo rises to 150 m above sea level, forming the highest elevation in the Caspian Depression. The hill is pushed up about 1 mm per year by a salt dome. Sinkholes, and Karst caves of up to 1.5 km length lead through the hill. It also is the only area in Europe where Triassic lagerstätten surface. To the local Kalmyk people, it is a holy hill.