Interesting trivia
The old glass of Notre Dame is thicker on the bottom than on the top because of the liquid properties of glass with the atoms moving so slowly...
Glass is basically a really thick liquid.
So in a way, the windows are “bubbles”. In theory, left long enough, a window would break as the glass settles on the bottom of the pain.
The old glass of Notre Dame is thicker on the bottom than on the top because of the liquid properties of glass with the atoms moving so slowly...