After reading the article " Unmastking the Face on Mars" the

Face on Mars is not created by aliens it is just a natural landform.

If the face on Mars was created by aliens that is "Evidence that NASA would father hide..." other wise "authors reasoned it would be a good way to engage the public and attract attention to Mars." and "It certantly did!" after that they used the face everywhere it was a pop icon as the articale says. " it starred in a Hollywood film, appeared in books, magazines, radio talk shows--evern haunted grocery store checkout lines for twentyfive years."

Mars Global Surveyor went and took another look at the face and got ten times better pictures than the Vikings did " Each pixel in the 2001 image spans 1.56 meeters, compared to 43 meters per pixel in the best 1979 Viking photo. As a rule of thumb, you can discern things in a digiral image three times bigger than pixel size..." meaning " you could see what they were!"

People were not satisfied so skeptics says that alien markings were hidden by haze but on the other hand "Thousands of anxiuos web surfers were waiting when the image fist appeared on a JPL web site, revealing...a natural landform. There was no alien monument after all.

Therefore the face on Mars is and could not be created by aliens at any point if it was NASA would want to keep that evidence hidden and would not have let everyone see the face.