Eye of the Sahara

Eye of the Sahara, is a prominent circular feature in the Sahara desert of Mauritania near Ouadane. It has attracted attention since the early space missions because it forms conspicuous bull's-eye on the otherwise rather featureless expanse of desert. Structure, which has a diameter of about 50 kilometers (31 miles) and is located 400-450 meters (1.310 to 1.480 ft) above sea level, has become important for the crew of the shuttle.

Eye of the Sahara is very visible at all when seen from space. And this place is still considered mysterious.