25 years ago NASA’s Viking1 spacecraft was circling the planet Mars, snapping some photos of possible landing sites for its sister ship Viking2, when it spotted the shadowy likeness of a human face. An enormous head nearly 3 miles from end to end seemed to be staring back at the camera from a region of the Red Planet called Cydonia. Today, we have more detailed images that show how wrong we were. Even though I for one would like to believe Face On Mars is a strong sign of some ancient civilization, we can see it was just an grand Optical Illusion, one of the most famous one to be precise. Jump inside this article for few more pictures and descriptions.
You can see the progress in high-res technology from 1998 to 2001 through resolution at which this photos were taken. Progress of detoriation is also visible. This sand dune looks like face only in certain conditions like: sun angle and camera position.