The Richat Structure

The Richat Structure
MAURITANIA
The Richat Structure, a prominent circular feature in the Sahara desert of Mauritania near Ouadane, has attracted attention since the earliest space missions because it forms a conspicuous bull's-eye in an otherwise rather featureless expanse of desert. The structure, which has a diameter of almost 50 kilometers, was intially interpreted as a meteorite impact structure because of its high degree of circularity, but is now thought to be a symmetrical uplift that has been laid bare by erosion.