For some reason I started watching YouTube videos of Notre Dame again. I came across one (in French) that deals with renovation activities from six or seven years ago. There is a great sequence that shows the casting of a set of new bells. It also deals with improvements to the organ, including the new console which Ryan did such a good job of modelling.
https://www.youtube.com/watch?v=Sw6Q8cuWn1Q&t=972s
I started to notice fleeting glimpses of areas that have intrigued me, so I kept hitting the pause button and taking screen shots. There are steps where the aisles of the choir hit the curve of the apse. It’s very difficult to get a clear view, because the flying buttresses get in the way. I was aware of this step, but I hadn’t realized that it contained little rows of windows. Something similar happens along the nave, but at a higher level. That was a mystery at first until we realized that the clerestory windows had been enlarged at a later date. Maybe the…