The desert is a modern phenomenon and a cemetery for ancient civilizations
We've been taught that the Sahara is a million years old, but usually, early maps seem to indicate otherwise
Somehow, cartographers of the sixteenth and seventeenth centuries did not consult modern historians about their governments today.
Instead, they depicted the desert as it was 450 years ago. What a beautiful location: lakes, rivers, cities, animals, etc.
Then for obvious reason humanity suffered a serious case of worldwide amnesia.
The entire continent was erased and had to be rediscovered.
It appears that a very powerful event practically wiped out the entire African continent just a few hundred years ago.
Hundreds of cities and towns were destroyed.
Of course, if you can come up with a suitable explanation, you can list it here. I have it in the comments