reflect cultural and natural changes in the area. The Tadrart Acacus have a large variation of landscapes, from different-coloured dunes to arches, gorges, isolated rocks and deep wadis (ravines). Major landmarks include the arches of Afzejare and Tin Khlega. Although this area is one of the most arid in the Sahara, there is vegetation, such as the medicinal Calotropis procera, and there are a number of springs and wells in the mountains.