It's a jungle out there. Well, it usta be...

 Between 10,000 and 5,000 years ago, the Sahara was a lush green savanna filled with lakes, rivers, and forests. Known as the African Humid Period, changes in Earth's orbit brought heavy monsoon rains that supported thriving wildlife and early human communities before an abrupt climate shift turned the region to sand.

 Hippos, crocodiles, elephants, giraffes, and antelopes roamed the grassy plains. Early people fished, hunted, and left behind rock art depicting vibrant local animals. Lake Chad grew to the size of the modern Caspian Sea.

Changes in Earth's tilt and orientation to the sun reduced summer solar energy and weakened monsoons. Instead of fading over millennia, the lush ecosystem transitioned into an arid desert within just a few centuries. As the rains stopped, inland populations moved toward the Nile Valley, helping fuel the rise of ancient Egyptian civilizations.

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