As seen from the International Space Station, the “Eye of the Sahara” (I was taught: the Eye of Africa) looks like a mining feature but it is not. It is actually a naturally occurring “dome structure” and is also known as theRichat Structure.
NASA: From an altitude of 255 miles, an Expedition 59 crew member photographed the Richat Structure, or the “Eye of the Sahara,” in northwestern Mauritania. The circular geologic feature is thought to be caused by an uplifted dome—geologists would classify it as a domed anticline—that has been eroded to expose the originally flat rock layers.
Image: NASA et al.