Mauritania, Ouadane: The Richat Structure
The Richat Structure, also known as the Eye of the Sahara, Earth’s Bull’s-Eye, the Eye of Africa and Guelb er Richat, is a prominent circular feature in the Sahara desert of west–central Mauritania near Ouadane. This structure is a deeply eroded, slightly elliptical, 40-km in diameter, dome.
Initially interpreted as an asteroid impact structure because of its high degree of circularity, it is now argued to be a highly symmetrical and deeply eroded geologic dome.
Ouadane or Wadan (Arabic: وادان) is a small town in the desert region of central Mauritania, situated on the southern edge of the Adrar Plateau, 93 km northeast of Chinguetti.
The town was a staging post in the trans-Saharan trade and for caravans transporting slabs of salt from the mines at Idjil.
A Portuguese trading post was established in 1487, but was probably soon abandoned. The town declined from the sixteenth century and most of the town now lies in ruins.
The old town, a World Heritage Site, though in ruins, is still substantially intact, while a small modern settlement lies outside its gate.
Ouadane is the closest town to the Richat Structure, a massive circular landmark visible from space.