In a remote part of northern Mauritania on the Adrar Plateau lies a desert landscape rich in human history. This region of northwestern Africa is sprinkled with Paleolithic stone tools, Neolithic cave paintings, and the remains ofmedieval townsonce used by caravans crossing the Sahara Desert.
When viewed from space, the landscape appears to be shaped most prominently by natural forces. Wind sculpted the seas of colorful sand dunes and scoured plateaus capped with darkdesert pavement, while ancient flowing water carved valleys and networks of dried river channels.
But the region’s most eye-catching feature when seen from above is the Richat Structure—a large geologic formation made of concentric ridges on the eastern side of the plateau. French geographers first described the feature in the 1930s, calling it the Richat “buttonhole.” NASA astronauts Ed White and James McDivitt helped bring wider global attention to what became known as“The Eye of the Sahara”afterphotographingit during their history-makingGemini IV mission.
The 40-kilometer-wide structure was initially thought to be animpact craterbecause large meteors can produce circular features on Earth’s surface. However,researcherslatershowedthat it is actually a deeply erodedgeologic domeformed by the uplift of rock above anunderground intrusionof igneous material. Over time, differingerosion ratesamong rock types in the exposed upper dome led to the development of circular ridges known ascuestas. The orange and gray colors reflect differences in sedimentary and igneous rock types across the structure and the surrounding landscape.
NASA Earth Observatory image by Lauren Dauphin, using Landsat data from theU.S. Geological Survey. Story by Adam Voiland.
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Abdeina, E.H., et al.How old is the Eye of Africa? A polyphase history for the igneous Richat Structure, Mauritania.Lithos, 107698.
Abdeina, E.H., et al.Geophysical modelling of the deep structure of the Richat magmatic intrusion: insights into its kinematics of emplacement.Arabian Journal of Geosciences, 14, 2315.
The DebriefThe Richat Structure: The “Eye of the Sahara” is One of Earth’s Strangest Marvels. Accessed April 8, 2026.
GĂ©oconscience,Adrar Plateau. Accessed April 8, 2026.
International Commission on Geoheritage,Richat Structure, A Cretaceous Alkaline Complex. Accessed April 8, 2026.
Matton, G., et al.Resolving the Richat enigma: Doming and hydrothermal karstification above an alkaline complex.Geology, 33, 665-668.
Matton, G. & Jébrak, M.The “eye of Africa”: An isolated Cretaceous alkaline–hydrothermal complex.Journal of African Earth Sciences, 97, 109-124.
NASA Earth ObservatoryThe Eye of the Sahara. Accessed April 8, 2026.
National ArchivesRichat Structure. Accessed April 8, 2026.
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