Face on Mars
Cydonia Mensae is an albedo feature (region) on Mars. It lies in the planet's northern hemisphere in a transitional zone between the heavily-cratered regions to the south and relatively smooth plains to the North. Cydonia itself is covered in numerous mesas and may have been a coastal zone if planetologists are correct in believing that the northern plains were once ocean beds.
One of the Cydonian mesas, situated at 40°45' north latitude and 9°26' west longitude, took on the striking appearance of a human Face on Mars in a photo taken by Viking 1 in 1976. While generally believed to be an optical illusion (pareidolia), others view it as evidence of a long-lost Martian civilization. Other features are argued to have been observed, such as apparent pyramids. A popular belief is that these are part of an ancient ruined city.
3D Face on Mars
NASA - April 21, 2007
New Visage for Red Planet 'Face'
BBC - September 22, 2006
The Mars Express probe has photographed the classic surface feature on the Red Planet's surface known as "The Face". The mountain, which looks just like a human head with eyes, mouth and nostrils, was first pictured by the US Viking 1 Orbiter in 1976.The formation instantly became the stuff of myth and conspiracy theories, with some claiming it was evidence of an ancient Martian civilisation.The new European images of The Face were taken in July this year.It has been something of a struggle for scientists to get a decent shot of the area in mid-northern latitudes referred to as Cydonia. The probe was either at too high an altitude when making a pass or had its view degraded by dust and haze in the atmosphere. A 22 July fly-over finally provided perfect conditions.
The new images even reveal a feature that looks like a skull
The probe used its High Resolution Stereo Camera to picture The Face and other geological structures around it in 3D. This requires imaging experts at the German space agency to post-process essentially flat, overhead shots to produce perspective images that give the viewer the impression they are flying over the surface in a light aircraft.
The results are some of the most spectacular views of the Red Planet ever seen. "These images of Cydonia on Mars are truly spectacular," said Dr Agustin Chicarro, project scientist for the European Space Agency's Mars Express mission." They not only provide a completely fresh and detailed view of an area famous to fans of space myths worldwide, but also provide an impressive close-up over an area of great interest for planetary geologists, and show once more the high capability of the Mars Express camera." Scientists are interested in Cydonia because it tells them about erosive processes on Mars.
Cydonia tells scientists about erosion on the surface of Mars
Cydonia is located in the Arabia Terra region and belongs to the transition zone between the southern highlands and the northern plains. This transition is characterised by wide, debris-filled valleys and isolated remnant mounds of various shapes and sizes. Mars Global Surveyor images taken at the turn of the century proved beyond any doubt that The Face pictured by Viking 1 was nothing more than a trick of the light; there was no evidence there of structures built by an ancient civilization, as some Red Planet fans had hoped. Mars Express imaged another popular surface feature earlier this year: the 230km-wide (143 miles) impact crater that looks like a smiley face.