Which Mauritanian geological formation is also called the Eye of the Sahara?

Mauritania’s Richat Structure is the geological formation often called the Eye of the Sahara.

Located near Ouadane on the Adrar Plateau, the Richat Structure appears from above as a vast set of concentric rings. Its striking circular pattern once encouraged speculation that it was an impact crater, but geological studies found no convincing evidence of a hypervelocity collision.

The formation is now understood as a deeply eroded geological dome associated with an ancient igneous intrusion and hydrothermal activity. Differential erosion exposed alternating layers of resistant and softer rock, producing the ringed landscape visible from space. The structure is about 40 kilometers across, though measurements and descriptions can vary.

Its space-age reputation grew after astronauts photographed it as a prominent landmark in the Sahara. It is also known as the Richat Dome or Guelb er Richât. Despite recurring popular theories, there is no accepted scientific evidence that it is the lost city of Atlantis.