These ancient towns were important cities to the caravans that crossed the Sahara desert
Oualata or Walata is a small oasis town in southeast Mauritania, located at the eastern end of the Aoukar basin.
Oualata is believed to have been first settled by an agro-pastoral people akin to the Mandé Soninke people who lived along the rocky promontories of the Tichitt-Oualata and Tagant cliffs of Mauritania facing the Aoukar basin. There, they built what are among the oldest stone settlements on the African continent.
The old town covers an area of about 600 m by 300 m, some of it now in ruins. The sandstone buildings are coated with banco and some are decorated with geometric designs. The mosque now lies on the eastern edge of the town but in earlier times may have been surrounded by other buildings. - in: wikipedia
The four towns (in red what I have):
- Ksour of Ouadane
- Ksour of Chinguetti
- Ksour of Tichitt
- Ksour of Oualata