One of Earth’s most impressive natural wonders—the Sahara Desert’s mysterious Richat Structure—just made a striking appearance in new satellite images released by NASA.
The curious feature, located in an isolated region of northern Mauritania on the Sahara’s mountainous Adrar Plateau, was first discovered almost a century ago but had not been photographed until it was spotted by astronauts during the Cold War.
The newest images of this geological marvel, captured on March 5 and 6, 2026, were recently featured as NASA Earth Observatory’s Image of the Day for April 16.
According to a commentary by Adam Voiland accompanying the newest images, the Richat Structure is “a deeply eroded geologic dome formed by the uplift of rock above an underground intrusion of igneous material.”
“Over time, differing erosion rates among rock types in the exposed upper dome led to the development of circular ridges known as cuestas,” Voiland adds. “The orange and gray colors reflect differences in sedimentary and igneous rock types across the structure and the surrounding landscape.”
The Richat Structure is not the only unique feature in the Sahara Desert that features striking concentric geology similar to this. Another example, Jabal Arkanū’s concentric rock rings, found in southeastern Libya, also bear a unique circular appearance, though not quite as striking as its massive Mauritanian counterpart.
A Cold War Discovery
On June 3, 1965, at the height of both the Cold War and the great Space Race between the United States and the Soviet Union, the Gemini IV mission lifted off from Launch Complex 19 at Cape Kennedy Air Force Station in Florida, carried into orbit aboard the Gemini–Titan II, a modified Intercontinental Ballistic Missile.
Only the 10th manned American spaceflight at that time, astronauts James McDivitt and Ed White spent four days in orbit, during which White performed the first American spacewalk, spending nearly 20 minutes outside the spacecraft. The pair made a total of 66 trips around the Earth and conducted several scientific experiments in space.
“The objective of the mission was to test the performance of the astronauts and capsule and to evaluate work procedures, schedules, and flight planning for an extended length of time in space,” reads an official NASA historical summary of the mission. “Secondary objectives included demonstration of extravehicular activity in space, conduct stationkeeping and rendezvous maneuvers, evaluate spacecraft systems, demonstrate the capability to make significant in-plane and out-of-plane maneuvers and use of the maneuvering system as a backup reentry system, and conduct 11 experiments.”
Prior to entering space, McDivitt and White had been asked to photograph the Earth from space, and while doing so, to pay attention to what appeared to be “any large circular features which might be the roots of impact structures.” While passing over one of the planet’s hottest and most unforgiving regions—the Sahara desert—the astronauts spotted something which, to them, did look like it might have been evidence of a crater of some kind, albeit a strange one.
Peering at the astronauts like a massive eye emerging from the Saharan sand was a huge, circular object or structure with a large central area encircled by rings of stone and sand extending in every direction for miles. At nearly 30 miles across, what the Gemini IV astronauts had easily observed—and photographed for the first time from space—had been a feature known as the Richat Structure.
Impact Crater, Ancient Volcano, or Something Else?
Although the Apollo era provided Earth with the first images of the mysterious feature, it had actually been discovered decades earlier, at least as early as the 1930s. By 1948, French scientist Jacques Richard-Molard was arguably the first to propose that the mysterious feature might have resulted from a sheet-like intrusion known as a laccolithic thrust.
However, upon its “rediscovery” by the Gemini IV crew in 1965, it was initially thought to have been an impact crater when it was observed from space. However, further studies showed it to have a flat central area and no shock-altered rock, which would have been a telltale indicator of an impact event. Other theories proposed included a volcanic eruption, which was later ruled out in favor of an uplifted region of rock sculpted over time by erosion, although its unusual circular appearance remains mysterious.
According to a Business Insider article from 2016, although questions remain about the structure’s formation, a pair of Canadian geologists speculate that the Eye of the Sahara’s origins began more than 100 million years ago, “as the supercontinent Pangaea was ripped apart by plate tectonics and what are now Africa and South America were being torn away from each other.”
According to the theory, the present dome of rock layers resulted from molten rock that was thrust upward, but never actually reached the surface. Thus, the Sahara’s strange Eye is essentially the geological equivalent of a pimple, surrounded by “ripples” in the form of fault lines. Limestone that was dissolved near the center of the formation by the accumulation of molten rock caused it to collapse, resulting in the breccia formation geologists observe there today.
Archaeology of the Richat Structure
In addition to being a geological wonder, the Richat Structure has yielded a wealth of archaeological data over the years. Ongoing studies at the site continue to assess the duration and extent of human occupation of the Sahara Desert’s most peculiar geological feature. An abundance of Acheulean artifacts has been recovered there, indicating the presence of early archaic humans who lived and hunted in the vicinity of the peculiar formation.
However, most of the archaeological sites observed in the area are associated with quartz outcrops from which early humans may have gathered material for making stone tools. The majority of archaeological locations around the feature lie along its outer ring on the northwestern side, and surveys beginning around 1974 have found little archaeological evidence of human presence within the inner depressions of the structure.
The mysterious Eye of the Sahara has become a landmark for spacefaring shuttle crews since McDivitt and White first spied it from space in 1965. Today, although many unusual natural phenomena have been detected from Earth orbit, the Sahara’s famous Richat Structure remains one of the most impressive natural features visible from space.
Editor’s Note: This is an updated version of an article originally published by The Debrief on April 16, 2021.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.