Around 9:45, still before sunset, I was on the Quai d’Orléans behind Notre-Dame while leaving the impressive Polish Library of Paris after the grand opening (vernissage) of an exhibit centered on the Polish/American sculptor Elie Nadelman – his early “études” on the theme of Beauty. What was striking to me at that hour was the stained glass window of the façade, clearly visible through to the rear of the vast cathedral, because the rear windows (behind the altar) have been removed for safety and for their restoration, while the walls that will support the new roof are being reinforced.