Teachable Moment: The Tacoma Narrows Bridge collapse has long been used as an example of forced resonance in physics text books but recent analysis suggests aerodynamically induced "forced excitation" (see second reference) may have been the cause. Either way, the video footage is dramatic and encourages great discussion!
The 1940 Tacoma Narrows Bridge was the first incarnation of the Tacoma Narrows Bridge, a suspension bridge in the U.S. state of Washington that spanned the Tacoma Narrows strait of Puget Sound between Tacoma and the Kitsap Peninsula. It opened to traffic on July 1, 1940, and dramatically collapsed into Puget Sound on November 7 of the same year. At the time of its construction (and its destruction) the bridge was the third longest suspension bridge in the world in terms of main span length, behind the Golden Gate Bridge and the George Washington Bridge.