The original Tacoma Narrows Bridge opened on July 1, 1940 and dramatically collapsed into Puget Sound on November 7 of the same year. The suspension bridge spanned the Tacoma Narrows strait between Tacoma and the Kitsap Peninsula. Its replacement was opened in the same location in 1950, and a second, parallel bridge opened in 2007. The instability in winds earned the nickname Galloping Gertie.

The bridge's collapse had a lasting effect on science and engineering. In many physics textbooks the event is presented as an example of elementary forced resonance with the wind providing an external periodic frequency that matched the natural structural frequency, even though its real cause of failure was aeroelastic flutter^[1] . Its failure also boosted research in the field of bridge aerodynamics/aeroelastics, the study of which has influenced the designs of all the world's great long-span bridges built since 1940.