Mauritania is the African country that contains the Richat Structure, a giant circular geological formation visible from space.
The Richat Structure, also called the Eye of the Sahara, lies in the Adrar region of north-central Mauritania. It is roughly 40 kilometres across and appears as a set of concentric rings in the desert. Although it was once considered a possible impact crater, geological research identifies it as a deeply eroded domed structure formed by uplift and later erosion.
The rings expose different rock layers, so their colors and textures vary across the formation. Wind and water erosion have gradually revealed the resistant and less-resistant rocks that create the striking circular pattern. Its visibility from orbit made it a useful landmark for astronauts and a famous satellite-image subject.
The structure is near Ouadane, a historic settlement linked to trans-Saharan caravan routes. It is not an artificial construction and is not generally classified as a meteorite crater.