One aspect of the Mars Global Surveyor (MGS) Extended Mission was the opportunity to turn the spacecraft and point the Mars Orbiter Camera (MOC) at specific features of interest. In April of 2001 engineers pointed the MOC at the popular "Face on Mars" feature.
Viking orbiter images acquired in 1976 showed that one of thousands of buttes, mesas, ridges, and knobs in the transition zone between the cratered uplands of western Arabia Terra and the low, northern plains of Mars looked somewhat like a human face. This illusion of light and shadow took hold in the popular imagination, giving rise to many theories of a vanished civilization on Mars.
Browse Image | Medium Image | Full Res Image