The Loretto Chapel is a former Roman Catholic church in Santa Fe, New Mexico, United States, that is now a privately owned museum and a wedding chapel.

It is known for its unusual helix-shaped spiral staircase (the "Miraculous Stair"). It has been the subject of legend, and the circumstances surrounding its construction and its builder were considered miraculous by the Sisters of Loretto, who credited Saint Joseph with its construction.

The staircase rises 20 feet (6.1 m) to the choir loft while making two full turns, all without the support of a newel or central pole. The staircase is built mostly out of wood and is held together by wooden pegs, with no glue, nails or other hardware used. The inner stringer consists of seven wooden segments joined together with pegs, while the longer outer stringer has nine segments. The exact wood used to build the staircase has been confirmed to be a type of spruce which is not native to New Mexico and scientifically not identified anywhere else in the world.

There are 33 stairs, which has been noted to be the age of Christ at the time of his death.

More Info: en.wikipedia.org