Cydonia is a region on the planet Mars that has attracted both scientific and popular interest. The name originally referred to the albedo feature (distinctively colored area) that was visible from Earthbound telescopes. The area borders plains of Acidalia Planitia and the Arabia Terra highlands. The area includes the regions: “Cydonia Mensae“, an area of flat-topped mesa-like features, “Cydonia Colles“, a region of small hills or knobs, and “Cydonia Labyrinthus“, a complex of intersecting valleys. As with other albedo features on Mars, the name Cydonia was drawn from classical antiquity, in this case from Kydonia, a historic polis (or “city-state”) on the island of Crete. Cydonia contains the “Face on Mars” feature—located about half-way between Arandas Crater and Bamberg Crater.
Cydonia was first imaged in detail by the Viking 1 and Viking 2 orbiters. Eighteen images of the Cydonia region were taken by the orbiters, of which seven have resolutions better than 250 m/pixel (820 ft/pixel). The other eleven images have resolutions that are worse than 550 m/pixel (1800 ft/pixel) and are of limited use for studying surface features. Of the seven good images, the lighting and time at which two pairs of images were taken are so close as to reduce the number to five distinct images.
In one of the images taken by Viking 1 on July 25, 1976, a 2 km (1.2 miles) long Cydonian mesa, situated at 40.75° north latitude and 9.46° west longitude, had the appearance of a humanoid face. When the image was originally acquired, Viking chief scientist Gerry Soffen dismissed the “Face on Mars” in image 035A72 as a “trick of light and shadow”. However, a second image, 070A13, also shows the “face”, and was acquired 35 Viking orbits later at a different sun-angle from the 035A72 image. This latter discovery was made independently by Vincent DiPietro and Gregory Molenaar, two computer engineers at NASA’s Goddard Space Flight Center. DiPietro and Molenaar discovered the two misfiled images, Viking frames 035A72 and 070A13, while searching through NASA archives.