The well tended ruins of the Augustinian Nunnery on Iona have walls that reveal layers and layers of history. The many changes the structure has obviously undergone (both additions and subtractions) are like clues. They reveal different periods and styles of stonework. The variations catch the eye and the imagination, at every turn. Those of us on the Tour of Stones, and thousands of other visitors to this sacred site, I'm sure, all feel a need to try to piece together the story of what happened here.