The Golden Gate Bridge turns 87 next week, and today we have a story that started — for us — on that iconic bridge, with a low hum that was "born" in 2020. That tale led us to a much bigger story, which we bring you today. The Hum is a mysterious low pitch noise that is only heard by 2% of people worldwide. It's annoyed residents in San Francisco's Sunset District. So, in this story, we get to the bottom of this strange global phenomenon.
The Hum heard 'round the world, explained
![An image of the Worldwide Hum Map, a catalogue of reports of The Hum around the world.](https://npr.brightspotcdn.com/dims4/default/8b4f9fc/2147483647/strip/true/crop/2130x1246+0+0/resize/880x515!/quality/90/?url=http%3A%2F%2Fnpr-brightspot.s3.amazonaws.com%2F94%2F5b%2Fafcecc1841c3a441cf8922f32da9%2Fworldwide-hum-map.png)
The World Hum Map and Database