The Loretto Chapel Staircase, also called the Miracle Staircase. Entirely self-supporting, no central column, and wooden pegs rather than nails. Built by an unknown carpenter who built it, then disappeared without pay.
Stairs in Melk Abbey (or Stift Melk), an Austrian Benedictine abbey, and one of the world's most famous monastic sites. It is located above the town of Melk on a rocky outcrop overlooking the river Danube in Lower Austria, adjoining the Wachau valley.