Jessica Meir Photographs Mauritania's 25-Mile Eye of Africa From ISS

Q: Why did a remote Saharan geologic anomaly captivate NASA astronauts for decades before becoming a global geoheritage site?

It captivated astronauts because the Richat Structure is one of the rare landforms whose meaning becomes clearer from orbit than from the ground. In Mauritania’s bare Sahara, its 25-mile-wide concentric rings stand out with unusual clarity, forming a near-perfect bullseye that is difficult to recognize at surface level but striking from space. That visual effect made it memorable to crews from Gemini IV in 1965 to today’s ISS astronauts, including Jessica Meir, who called it “pure Earth Art.” Its scientific mystery deepened that appeal. For years, the formation was widely thought to be an impact crater because it looked like one from above. Orbital photographs reached the public before geologists had settled the question, helping turn it into a global curiosity. Later research showed it is not a meteor scar but an uplifted dome shaped by igneous intrusion, hydrothermal alteration, collapse, and millions of years of erosion, with harder and softer rocks weathering into the ringed pattern. That combination of dramatic appearance and geological importance explains why fascination lasted for decades and eventually became formal recognition. The Richat Structure was not discovered from space, but spaceflight revealed its full scale to the world. As scientists refined its origin and its value as an exceptional natural record of Earth processes became clearer, the International Commission on Geoheritage designated it a site of global geoheritage significance in 2022.

2 articles · Updated · Space.com · Aug 20

Jessica Meir shared a new ISS photo of Mauritania's Richat Structure, a 25-mile-wide geologic formation known as the "Eye of Africa."
Meir said the day's lighting and coloring caught her "artistic eye," highlighting the concentric ridged rings that make the feature stand out from orbit.
The Richat Structure is a natural formation whose massive scale makes it especially clear from space, where astronauts can see its full circular pattern.
NASA astronauts first photographed the landmark from space in 1965 during Gemini IV, and Meir captured the latest view 61 years later while serving on Expedition 75.