Tibesti

Range in the central Sahara, on the borders of Libya, Niger, and Chad; the highest peak is Emi Koussi at 3,415 m/11,208 ft. The mountains are some 500 km/310 mi long and 300 km/205 mi wide

The mountains are a block of volcanic rock that forced their way through the surrounding sandstone plateau and now form a residual mass. Dry watercourses and wildlife drawings on rock paintings in the region indicate that the climate was formerly less arid.