Within the Saharan Desert is a large structure measuring 6 kilometers across which contains numerous concentric circles. This feature is a 6 kilometer wide impact crater which formed while the area was a green grassland. Known as Tin Bider crater, it provides an excellent example of a complex crater within the African continent. This video will discuss this crater, how it formed, and mention what effects its formation had.
Source : http://patreon.com/geologyhub.