The largest desert on Earth stretching from the Atlantic Ocean to the Red Sea on the African continent. Countries which lie within the Sahara Desert are Morocco, Algeria, Tunisia, Libya, Egypt, Mauritania, Mali, Niger, Chad, and Sudan. The Nile River and the Niger River cross through it.

Scientists believe that 4,000 years ago the Sahara region had a much wetter climate with a savanna environment. The tilting of the Earth's axis caused an abrupt change in climate and vegetation (such as more sunlight and an amplified monsoon season) causing the desertification of the Sahara region.