In November 1940, the Tacoma Narrows Bridge collapsed due to a combination of high winds and poor construction. In this footage, the bridge can be seen literally waving and twisting for several minutes before finally collapsing into Puget Sound.
I had seen clips of this collapse many times, but never the full segment until now, and I didn't know where it was until now. Very interesting. It's good to no they were somehow able to get everyone off the bridge in time... aside from a reporter's dog, unfortunately.
Even more interesting is how this footage can still be used today (2016) in a physics class to explain the wobbling the swaying. Can't say I ever learned it, but then again, I never got far enough in physics to see some of those elaborate equations.