Dominant groups of people are Sahrawis , Tuareg and Negroids. The largest city is Nouakchott , Mauritania's capital. Other important cities are Tamanrasset , Algeria and Ghat, Libya. Sahara is very dry but there is an annual rainfall on most regions, but this is just a couple of millimetres. Some mountain peaks are covered by snow in the winter.
Animal life is limited to gazelles, antelopes, jackals, foxes, badgers and hyena.
The spread of Sahara is part of a process starting at least 8,000 years ago, when this region was still fertile. The few fertile regions today are fed by underground rivers and underground basins.