Lakes of Ounianga are a series of lakes in the Sahara Desert, in North-Eastern Chad, occupying a basin in the mountains of West Tibesti and Ennedi East. It was added as a UNESCO World Heritage site in 2012. 

According to the UNESCO description, the lakes are in a hot and hyperarid desert that features a rainfall of less than 2 millimetres (0.1 in) a year. The lakes exhibit a variety of sizes, depths, chemical compositions and colorations.

The lake system dated back to 10,000 years ago, the water is provided by the underground waterways making it the only lake system in the world with colorful lakes (blue, green, light red due to the chemical composition of each lake).

There is a total of 18 lakes in groups as follows:

Ounianga Kébir group: Lake Yoa, Lake Katam, Lake Oma (or Ouma), Lake Béver, Lake Midji, Lake Forodom;

Lake Motro, about 30 kilometres (19 mi) southeast of Ounianga Kébir;

Ounianga Sérir group about 45 to 60 kilometres (28 to 37 mi) southeast of Ounianga Kébir: Lake Melekui, Lake Dirke, Lake Ardjou, Lake Téli, Lake Obrom, Lake Élimé, Lake Hogo, Lake Djiara, Lake Ahoita, Lake Daléyala, and Lake Boukkou.

The total surface area of the lakes is about 20 square kilometres (8 sq mi). The largest of the lakes, Lake Yoa, has about a 3.5-square-kilometre (1 sq mi) area and attains 20 metres (66 ft) in depth.

According to en.wikipedia