The Sahara desert was a lush, green landscape with lakes and rivers just a few thousand years ago.

Roughly between 11,000 and 5,000 years ago, a period known as the African Humid Period, seasonal monsoon rains shifted northward and transformed much of what is now the Sahara desert into savanna, grassland, and wetlands, dotted with lakes and rivers that supported hippos, crocodiles, and giraffes. Rock art found deep in the modern desert, depicting swimmers, cattle herds, and aquatic animals, confirms that humans lived and thrived across the region during this greener era.

The shift back to desert happened over a few thousand years as gradual changes in Earth’s orbital tilt weakened the monsoon system, and vegetation loss likely accelerated the drying through feedback effects on rainfall. Today the Sahara is the largest hot desert on Earth, a striking reversal from its condition just a few millennia ago.