The Eye of the Sahara: The Richat Structure

Astronauts love gazing at the Eye of the Sahara from space, where it resembles a 40 km-wide flying saucer landing site. In reality, it’s just the remains of a dome that’s taken 100 million years to erode.

This circular feature in the Sahara Desert of Mauritania, with a diameter of almost 30 miles, has caught attention since early space missions due to its circular shape in an otherwise featureless desert. Initially thought to be a meteorite impact, it’s now considered a symmetrical uplift revealed by erosion, with Paleozoic quartzites forming the resistant beds. The Richat Structure looks great from above, but not so much from below.