ISS002-E-5693 (19 April 2001) --- The "bull's-eye" of the Richat Structure adds interest to the barren Gres de Chinguetti Plateau in central Mauritania in northwest Africa. It represents domally uplifted, layered (sedimentary) rocks that have been eroded by water and wind into the present shape. The 25-mile-wide structure is a 300-foot-deep landmark that has caught the eye of many an astronaut in Earth orbit. Image number ISS002-E-5457 shows the same feature six days earlier. The image was recorded with a digital still camera.