Lakes of Ounianga - Chad

Not so long ago I've received my very 1st card from Chad, which was from a UNESCO site. Last month I've received a second one, also from a WHS and also sent by Svenja. 

Lakes of Ounianga and Ennedi Massif are the only UNESCO sites of this African country.

Getty Images / Michael Runkel

The Lakes of Ounianga are found in the heart of the Sahara Desert, in an area of northern Chad that receives no more than 2mm of rain annually. They depend on an underground supply of ‘fossil’ water that fell on the area in ancient times when the Saharan climate was much wetter than it is today.  The lakes are situated in a shallow basin below sandstone cliffs and hills, from where the ancient water flows.  Remarkably, this unique hydrological system is able to sustain the largest permanent freshwater lakes to be found in such an arid desert environment anywhere in the world.

There are 18 lakes altogether, in two groups about 40 km apart.  They vary greatly in chemical composition, some being so salty that they can only support the most basic forms of life, while others are fresh enough to provide habitat for aquatic plants, fish and a diversity of other species. - in: https://www.africanworldheritagesites.org