The Sahara once held a lake 48% larger than all five Great Lakes combined, but Mega-Chad vanished about 5,000 years ago

Roughly 6,000 years ago, the middle of what is now the southern Sahara held a lake larger than all five North American Great Lakes combined, spread across about 361,000 square kilometres of open water. Today, only Lake Chad remains as the surviving surface-water remnant of that much larger system, shared by Chad, Niger, Nigeria and Cameroon, while the ancient lake basin stretches far beyond it.

Raccontata datimesofindia.indiatimes.com