The Golden Gate Bridge sings

The slats in the Golden Gate bridge will resonate at certain wind speeds and directions. the first is a low-pitched + low-frequency tone between 280-700hz created by westward ~22mph winds while the second tone is of a higher pitch + frequency of 1.1khz created by ~27mph winds. 

This is the singing as heard from Lone Mountain, during a rainy night.

Recorded by wwjd (Jason Talsma).