The footage above is of "Galloping Gertie" from November 7, 1940, the day that the Tacoma Narrows Bridge, which connects Tacoma to the Kitsap Peninsula, collapsed in an intense windstorm.
At the time this footage was shot, Gertie was the third longest suspension span in the world. It had opened for traffic just four months earlier on July 1st.
The bridge got its nickname "Galloping Gertie" because of the vertical movement of the deck observed by construction workers during windy conditions.
That movement, caused by not having the correct venting for high winds to pass through rather than slam the deck full force as wind might be caught by a sail on a ship, was a harbinger of bad things to come.
After that fateful day Gertie became known as "the most dramatic failure in bridge engineering history."
Today it is on the National Register of Historic Places as one of the world's largest man-made reefs (to keep people from trying to salvage it).
When Gertie collapsed she sent shock waves around the world, everywhere there was a suspension bridge or plans to build one.
The collapse of the Narrows Bridge led to the design and construction of safer suspension bridges that we use today.
The replacement narrows bridge was opened on October 14, 1950 and still stands today as the westbound lanes of the present-day twin bridge complex.