
A wind glass vibrated by sound at its resonance frequency.
The Golden Gate did have some issues with a loud hum caused by recent work but that has since been fixed.
thanks for your post, I’m seeing articles now on the humming of the SFG bridge.
My recollection was incorrect, although the event did happen. For the 50th anniversary celebration in 1987, the bridge was closed for pedestrians only, and some 300,000 people were on it at the same time, causing the center span to flatten from its normal slightly-flexed position.
So it was sheer weight and not some type of harmonic effect.