San Francisco's Golden Gate Bridge has long been something tourists flock to see. But now it's something people in the area can also hear — on a windy day, the landmark bridge actually emits a humming sound, puzzling and irritating many people on social media.
"Can someone explain to me why is this eerie sound has been going on for an hour," said one.
Resident Mark Krueger is a tech consultant who lives four miles from the bridge, and tweeted out a viral video of the noise.
"You can hear the different tones that are coming from the bridge and it's pretty amazing — it's overwhelming.
So what's causing all the noise? It's all part of a new project on the 83-year-old bridge that makes it more aerodynamic and resilient to high winds.
“The slats on the new handrail are much thinner than the old hand rail which means that air can flow more freely across the bridge," explained Paolo Cosulich-Schwartz of the Golden Gate Bridge District.