Tin Bider impact crater

Tin Bider (Arabic: تن بدر‎) is an impact crater that sits in dry, rugged terrain in Algeria.^[2] The crater was formed in the last 70 million years, perhaps in the late Cretaceous or early Tertiary Period.^[2] Spanning 6 kilometres, the crater sits at the southern end of a range of hills.^[2] The elevated position and concentric rings of Tin Bider suggest that its structure is complex.

• http://en.wikipedia.org/wiki/Tin Bider crater