
I was going to save this one for last, because it was the most interesting story I came across while researching for The Unearthed, but it's just so fascinating I had to write about it now.
The Faces of Belmez, or the Belmez Faces, whichever you prefer, have sparked intense scientific and pseudo-scientific debate.
A little background is necessary. In 1971, Maria Gomez Pereira noticed that a strange image had spontaneously appeared on her kitchen floor, that seemingly of a face. The part of the floor containing the offending face was ripped out and re-laid with cement. A week later, another face appeared in the same spot.
As it turns out, the house had been constructed over a cemetery. I know, sounds like a bad horror movie, but apparently this is all "true." Needless to say, an excavation ensued, bodies were reburied elsewhere, and life went back to normal. For two weeks.
Then another image appeared, and another, and eventually as many as 15 other faces appeared. Some would disappear and reappear in the course of a day, while some would remain in place for much longer. The floor was torn out a number of times and replaced, but the faces kept coming back no matter what was done.
Over the course of 35 years, the faces were photographed and documented by various reporters and scientists. One investigator sealed and covered the floor with plastic so it couldn't be tampered with, but new faces appeared underneath the plastic. Other tests were performed to determine if there were any chemical traces that would suggest that the faces had been drawn, and these tests, depending upon who you ask, yielded some surprising answers.
Some believe these images to be thoughtographic phenomenon. According to paranormal experts, this is a form of psychokinesis, in this case caused wittingly or unwittingly by the owner of the house, where the person psychically burns an image from the mind onto something else. Think The Ring. Others have claimed that there is chemical evidence of forgery.
This blog, My Favorite Monsters, provides an excellent detailed summary. And, there's this gem on youtube, complete with its own Matrix-soundtrack.