All this stuff, whether it be "Noah's Ark" or the "Butt on Mars" artifact, just cracks me up. Since everybody has already seen photos of the "Old Man of the Mountain" in NH as an example of a naturally occuring phenomonon that has the appearance of being man-made, I'll skip it and go to something different:
Try doing a search on the "Giant's Causeway" a "genuine" (wink-wink) "staircase" used by "Giants" to walk from Scotland to Northern Ireland.
I'll bet no one can prove Giants DIDN'T use it!
The 'Giants Causeway' is a natural phenomenon.