The face was not created by aliens on mars. The things that make it appear as a face are the shadows and the quality of which the picture was taken. The Face is just a rock formation, the fact that the shadows make it look like a face is simply just a coincidence.

If you look at the picture of the Face, you can see the black shadows on the figure, if you were to remove those shadows, it would most likely not look like a face anymore. The passage says "Scientists figured it was just another Martian mesa, common enough around Cydonia, only this one had unusual shadowss that made it look like an Egyptian Pharaoh." The passage also says "huge rock formation . . . which resembles a human head . . . formed by shadows giving it the illusion of eyes, nose, and mouth." Key word, illusion.

The original picture shown in the passage wasn't taken at a very high quality. The passage states "And so on April 5,1998, when Mars Global Surveyor flew over Cydonia for the first time, Michael Malin and his Mars Orbiter Camera (MOC) team snapped a picture ten times sharper than the original Viking photos. Thousands of anxious web servers were waiting when the image first appeared on a JPL website, revealing . . . a natural landform. There was no alien monument after all." This paragraph clarifies that the low quality original picture, along with the shadows, is what made it appear as a face. The Face is just a rock formation that looks like a face, nothing more than that.

All in all, the Face was not made by aliens and it is just a rock formation with a cool looking shadow. Though these alien theories are fun to believe in, the alien theory of this case is false.