This Giant 'Eye' in the Desert Is So Distinct That Astronauts Use It as a Landmark

In the Sahara Desert in Mauritania sits a gigantic, almost perfectly circular geological structure dozens of kilometers across, made up of concentric rock rings — known as the Eye of the Sahara or the Richat Structure.

The formation is so distinct and regular that for years it was mistaken for a meteorite impact crater, but current geological understanding points instead to uplifted rock that was later exposed and shaped by erosion.

The structure is so vast that its full, symmetrical shape is hard to make out from ground level — it only really becomes visible from great height, which for decades has made it a distinctive landmark for astronauts observing Earth from space.

Despite the seemingly uniform desert surroundings, the different rock rings of the Richat Structure vary in hardness and resistance to erosion, which over time made their pattern stand out and gave the formation its iris-like appearance.