Let me clear something up for you. The picture of 1976,1998 and 2001 was not created by aliens. I know that becasue how would the aliens know how to build an egyptian pharoah. Plus the they sent to mars was just taking pictures of a landing site for viking 1's sister viking 2. The first time they saw the face was when it was all shadowy so you could barely see it but as time past by it was 1998 when they went back up to mars with oe of the vikings to take another picture and it was more clear. They had to 12 years to go back up to mars and I dont think that aliens could build it that fast, it would've at least taken more time to make a good face. Then at the year 2001 they took another picture and it was fading away and I honestly dont think that the aliens would be able to take the face down that fast and why would they have to take it down. It has to be natural because there are no suh things as aliens, because no one from nasa has ever seen one and if they would've Nasa would've told everybody that they have found aliens and that they are real. Also I know its natural because even nasa said that the face had a nose,eyes,mouth, and looked exactly like a humans face.

How would an alien know what a humans head looks like? When nasa was taking pictures the head from a red planet called cydonia was looking back at the camera. Also maybe the head only appears on different years.