End of the Green Sahara
The savanna dries out and people head for the Nile
For millennia the Sahara was a savanna of lakes, giraffes and hippos, as rock art records. By about 3000 BC, by most estimates, the humid period had ended in stages and people moved to the Nile, just as a unified Egyptian kingdom arose there.
Wikipedia (English) · 31st century BC
Meanwhile around the world (±25 years)
Europe
- c. 3000 BC–2000 BC Building of Stonehenge — same year