Key to the puzzle

Key to the puzzle, originally uploaded by freckles~.

Part of a mosaic of the top of the dome in St. Peters Basilica, Vatican City, rome
this is up in the dome 114 feet above the church floor. You have to climb up the narrow steps, through the walkway that has the wall sideways because you are in the dome and then out to a 3 feet wide walkway. These mosaic’s are about 10-15 high so they can be seen from below. There are no painting in St. Peter’s everything on the walls is done in mosaic.