This photo, taken March 2, 2002, shows the outcrops of Jebel Auenat that rise 6,000 feet above the plains of the Libyan Desert. Sand moves around these outcroppings. The Sahara is the largest desert in the world. Experts say that it regularly grows and shrinks. One of the hottest places on the planet, the Sahara gets less than three inches of rain per year.