Khar nuur or the Black Lake located in Western Mongolia’s Valley of Lakes, part of a system of closed basins stretching across central Asia. These basin are the remnants of larger paleolakes /paleo means ancient/ that begun to shrink approximately 5000 years ago as regional climate became drier. Like other lakes in the region. Khar Nuur relies on precipitation, growing in the spring and shrinking in the summer. The lake is encircled by sand dune fields that encroach on the lower slopes of the Tobhata mountain to the west an d south.