[RedDevil]

Glass can only take so much before it breaks. It builds up tension that can be latent for years until the final straw unloads it.
If they hadn't run that test before the unveiling the windows would have coped well.

My parents used to have a long narrow low table of which the top was a sheet of glass supported by the corners. It was more than a meter long and at least 10 mm thick and quite heavy. It has taken a lot of abuse over the years, including me as a toddler using it as a trampoline. When my parents pulled me away they marveled that the glass did not break as they saw it bend down deep.

Then one day someone dropped a tiny fragile worked crystal liquor glass on it from maybe 10 cm above its surface. An enormous bang as it shattered in hundreds of flints. And right in the middle of the carnage was the liquor glass, unharmed...