Call me crazy, but I've begun to wonder if there isn't something extra terrestrial about it.   Ok, I'll call you crazy, and add some extra crazy to your comment.         There have been a large number of those "cone head,"  alien looking skulls found throughout Mexico, and particularly  along the border.  Nobody knows what culture they are from, or how they were able to deform their skulls to that degree.  Maybe they really are alien skulls.  They sure look like it.                                      Then there is the whole Pueblo indian tribes thing, and their long rumored connections with extra/ultra-terrestrial encounters.  Some of the native people of that region have even gone so far as to claim that gates to other world's have been opened in modern times.  There are a number of native American legends throughout that area that allude to possible alien encounters.