Tin Bider (Arabic: تن بدر) is an impact crater that sits in dry, rugged terrain in Algeria.[1][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.