Olympus Mons is one of the broadest volcanoes and certainly the tallest in the Solar System. It has been extensively described and analyzed in scientific publications and frequently noted in the popular and nontechnical literature of Mars. However, the first name given to the feature-Nix Olympica (Schiaparelli, 1879)-was based on its albedo, not its size, because early telescopic observations of Mars revealed only albedo features and not topography (lnge and others, 1971). After Mariner 9 images acquired in 1971 showed that this albedo feature coincides with a giant shield volcano (McCauley and others, 1972), the name Olympus Mons was adopted for the shield to distinguish it from the albedo feature.
Olympus Mons is one of the most photographed features on the planet. The Mariner 9 spacecraft obtained 126 images of Olympus Mons with resolutions of 60 m/pixel to 2.5 km/pixel. Later, the two Viking orbiters greatly enlarged this dataset, acquiring more than 2,150 images of the Olympus Mons region at various resolutions and altitudes; 925 images have resolutions of better than 50 m/pixel. More than 150 of the Viking images provide stereoscopic coverage of the shield region (Blasius and others, 1982).
