The Tuareg people, among others, have lived in the Sahara desert for thousands of years. Prior to its desertification, the area now occupied by the Sahara was relatively lush and was also more heavily populated than it has been for the past several centuries.
Though the Sahara is a large area, occupying about 3.5 million square miles in the northwestern part of the African continent, it is now very sparsely populated, mostly by nomadic Berber peoples such as the Tuareg. This harsh landscape has a long human history that is perhaps surprising to those who would assume that people wouldn't be able to survive in such a climate.
Camels are perhaps one of the most important survival tools that Sahara-dwelling people have. These hardy animals are able to travel through the sandy landscape and can survive for long stretches without having access to water. Humans, however, do need access to water, and the Tuareg people have been using the same routes through the desert for years in order to maximize access to water supplies as they travel. In some cases, these routes are hundreds of years old, allowing each successive generation to pass on valuable survival information. These are the sorts of techniques that allow these people to live in one of the harshest climates on the planet.