@Belilav 22 July 2021 more from that month

The Sahara is not just a desert and sand as we are used to saying. There is something that is barely noticeable but still visible even from space and that is around the Sahara. Around the Sahara is actually a series of concentric, slightly elliptical circles, and its diameter is between 40 and 50 km. The sedimentary rock located in the center of the dome dates back to the late Proterozoic period, ie 2.5 billion years ago, while the sandstone (sandstone) around the edges is about 480 million years old.