Loretto Chapel is best known for its "miraculous" spiral staircase, which rises 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 and glue rather than nails or other hardware. The inner stringer consists of seven wooden segments joined together with glue, while the longer outer stringer has nine segments. The exact wood used to build the staircase is unknown, although it has been confirmed to be a type of spruce, probably non-native to New Mexico.