For the one in New Mexico: Loretto Chapel, Santa Fe (1878), I think I saw that one featured in a show like "Unsolved Mysteries" (the good version with Robert Stack). The nuns needed a better way to get upstairs but didn't want a huge staircase taking up all of the space, so the prayed on it. A mysterious man showed up one day and offered to build that spiral staircase that has no central pillar. Once finished, he vanished and was never seen again.
For the one in New Mexico: Loretto Chapel, Santa Fe (1878), I think I saw that one featured in a show like "Unsolved Mysteries" (the good version with Robert Stack). The nuns needed a better way to get upstairs but didn't want a huge staircase taking up all of the space, so the prayed on it. A mysterious man showed up one day and offered to build that spiral staircase that has no central pillar. Once finished, he vanished and was never seen again.