Taken by Viking Orbiter 2 as it approached the dawn side of Mars, in early August 1976, this photo shows the results of computer enhancement. At the top, with water ice cloud plumes on its western flank, is Ascreaus Mons, one of the giant Martian volcanos. In the middle is the great rift canyon called Valles Marineris, and near the bottom is the large, frosty, crater basin called Argyre. The south pole is at the bottom.
