In 1976, the Viking spacecraft orbiting Mars took a picture. Well, it actually took many pictures, but there was one of particular interest to some people at Goddard and then the general public. This picture shows a structure that looks kind of like a human face:
The paper originally suggesting this feature looked like a face was originally dismissed for a few reasons, but people did continue to study it. Carlotto (my guess is for his own curiosity and for the interest of the public) performed a fairly extensive analysis of the image above along with one taken 35 orbits later. He cleaned up the data as best he could and then, using the two images, attempted to make a 3-D reconfiguration of the rock to see if the features persisted. I must say, I am fairly impressed with this paper. Carlotto only presents his opinion, that the feature might be artificial, near the end of the paper and only in one sentence. During the rest of the paper, he focuses mostly on explaining his methods and analysis.
I would say that his only flaw would be trying to pull too much information out of his crappy data. I also feel he should have used the other two images (although low resolution), because two data points is simply not enough to make a proper 3-D model of anything, especially if they two data points are from roughly the same angle at roughly the same time of day (Mars day). His 3-D model results (which he displays from different simulated camera positions) look near exact to the original image:
I agree with the original non-believers though. We humans are great at finding faces in just about any kind of rock: Old Man of the Mountain, the Romanian Sphinx, the Pedra da Gávea, the Old Man of Hoy, Stac Levenish, and the Badlands Guardian.
For anyone interested, here’s what the face looks like when you have nice data:
I mean, it looks really neat! It is still a nicely shaped, elliptical-ish mound. There even appear to be sand-drift (or maybe water) channels running off it. It just definitely looks like a rock though. This picture is courtesy of the Mars Global Surveyor from 1996. The Mars Reconnaissance Orbiter (2005) also imaged this area, but it looks about the same as above: no face. And this kind of makes sense! If life were to take as long to arise on Mars as it did on Earth (which hopefully would have occurred when it was still wet), then any civilization would have been recently died out, and anything they left behind would be visible yet subject to weathering. With its sad atmosphere and lack of water cycle, Mars no longer has as much weathering as it maybe did at one point, but any “face” made by a civilization would not last. (Also, who would make a mile long face?? At least our large structures on Earth are visually appealing when you’re next to them and don’t require spacecraft to admire.)