The Ennedi Plateau is located in the northeast of Chad, in the regions of Ennedi-Ouest and Ennedi-Est. It is considered a part of the group of mountains known as the Ennedi Massif found in Chad, which is one of the nine countries that make up the Sahelian belt that spans the Atlantic Ocean to Sudan. The Ennedi is a sandstone bulwark in the middle of the Sahara, which was formed by erosion from wind and temperature. Many people occupied this area, such as hunters and gatherers (5,000-4,000 cal BC) and pastoralists (beginning 4,000 cal BC). The Ennedi area is also known for its large collection of rock art depicting mainly cattle, as these animals were the main source of financial, environmental, and cultural impact. This art dates back nearly 7,000 years ago. Today, two semi-nomadic groups, mainly of the Muslim religion, have permanent villages in the Ennedi during the rainy months and pass through the area during the dry season. They rely on their herds of camels, donkeys, sheep, and goats to survive. Landscape and climate The Ennedi makes up an area of approximately 60,000 km2 (23,000 sq mi), as large as Switzerland, and its highest point is approximately 1,450 m (4,760 ft) above sea level. The Massif is composed of sandstone overlaying a Precambrian granite base. In the Ennedi, there are at least twenty perennial or semi-perennial springs, gueltas (desert ponds), and pools, but they rarely reach greater than a few dozen meters in the dry season. It is considered part of the Sahelian Acacia savanna, which extends across the entire continent which once contained diverse ungulates whose population has since been reduced. The landscape has geological structures, including towers, pillars, bridges, and arches, which serve as major tourist attractions. Interestingly, much of the sand found in the Sahara is due to the generation of dust in the Tibesti-Ennedi triangle. Evidence of a change in climate occurred between 6000 BP, with a savanna region with ~250 mm annual rainfall, to ~150 mm annual rainfall 4300 BP. It later reached an annual rainfall of 50 mm around 2700 BP, similar to the amount of annual rainfall observed today. There are also monsoons common in the area, generating around 50–150 mm of rain per year. These natural disasters create a diverse mixture of vegetation within the area. However, precipitation allows for greater moisture in the thin soil during the winter months,