I can see why you can think that "the Face on Mars" is some form of proof that either alien life did at one time or is still cuurrently on Mars . The human mind is meant to think, imagine and wonder "what if". Let's say these "aliens" are in fact real and constructed "the Face" in order to communicate with us. Carving a giant face has got to be one of if not thee least effective way of dong so.

These "aliens" very well could have simply just put a peice of shiney metal on the surface and the MGS would have seen it and we would probaly think "hey, this unknown element is here on the surface of a planet where there are no metals". Not only would it make us think that there is indeed metals on Mars but then we would think "hey metals most usually form deep undergroud so there is no reason for this to be on the surface". THAT would be a valid way of letting us know "hey, we exist".

Also another thing, if "aliens" made "the Face" how is it no footprint s were found. And there's no wind on Mars they coulnt have blown away. Seriusly, that's a big project so you're gonna need a lot of your alien buddies to help you out with it and no footprints....hmm. Well hey,maybe they have got giant eagle wings and fly everywhere. Yeah, on a planet that HAS NO GRAVITY!

Let's face it though (ha, face, get it?) everybody loves a good "supernatural " story. I believe that this is nothing more. "Once in 1976 a NASA spacecraft was looking for a place to land, and there on the surface they found... a huge human's face carved out of the surface Mount Rushmore style....wooouuh"

In conclusion, The very thought that "aliens" somehow carved a face onto Mars is ridiculis . And the final nail in the coffin? When you hear "conspiricy theorist" you think of a frail, usually middle aged, pale becuase he hasn't stepped out of his trailer in weeks, guy with a aluminum cone on his head and always taling about how"The Man" is out to get him.

Also he is dirty becuase hasnt shaved or showered in like a year. His trailer that's in the middle of nowhere has got newspaper

Scoch taped on the windows and the inside is filled with shelves of "alien communicating devices" (Yeah well, tell E.T. I said Hi)