The face on Mars was seen by fairly early probes. At the resolution
they had it does indeed look like a face. Subsequent higer resolution
work proved it to be simply a continuation of an outcrop all be it with
an unusual shape.

I am a retired scientist. I used to work in the field of Image
Processing and Artificial Intelligence. You can probably guess
something like that from the tone of my comments. One thing I have
thought about is what happens when we approach a person from a
distance. How much of a face do we have to resolve out before we
recognize it as a face? If we resolve a face into circular harmonics we
can answer this. The face on Mars comes well within my rough and ready
calculations.

Mars may well have had life of some sort but that life was certainly
not intelligent. Had aliens landed on Mars, what they would have left,
if anything, would not have been a Neolithic/Bronze Age style stone
monument, but a Von Neumann probe, and a self sustaining small colony.