Ancient Cities

 https://www.naturallymorocco.co.uk/itineraries/1504-17-ancient-cities-desert-mountains/

Of course some cities are much older than others.

https://www.aljazeera.com/gallery/2023/6/4/mystery-of-the-desert-lost-cities-of-the-nigerien-sahara

While some newer cities might become a lot larger than some of the ancient ones.

https://www.aljazeera.com/gallery/2023/6/4/mystery-of-the-desert-lost-cities-of-the-nigerien-sahara