Legend has it, these stairs were created by an expert carpenter whose identity has never been revealed. So what?
Well, the real mystery is how the stairwell is engineered to work, without a central pole with wooden pegs, no nails, and no attachment to a wall!
While I would not try building staircases like this at home, I would recommend a visit if you're ever in Santa Fe, New Mexico!
For more research and different theories surrounding this story, look up "The Mysterious Staircase".