Tacoma Narrows Bridge

The Tacoma Narrows Bridge opened to traffic on July 1, 1940. Its main span collapsed into the Tacoma Narrows four months later on November 7, 1940, due to a physical phenomenon known as aeroelastic flutter caused by a 42 mph wind. The bridge collapse had lasting effects on science and engineering. In many undergraduate physics texts 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 the cause of the bridge's failure was determined to be aeroelastic flutter). Its failure also boosted research in the field of bridge aerodynamics/aeroelastics which have themselves influenced the designs of all the world's great long-span bridges built since 1940.

No human life was lost in the collapse of the bridge. However, a small dog perished after it was abandoned in a car on the bridge by its owner, Leonard Coatsworth, and by another man, both of whom were bitten by the terrified dog when they attempted to remove it. The collapse of the bridge was recorded on 16mm film by Barney Elliott, owner of a local camera shop, and shows Leonard Coatsworth leaving the bridge after exiting his car. In 1998, The Tacoma Narrows Bridge Collapse was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant." This footage is still shown to engineering, architecture, and physics students as a cautionary tale.

Dismantling of the towers and side spans, which survived the collapse of the main span but were damaged beyond repair, began shortly after the collapse and continued into May 1943. The United States' participation in World War II as well as engineering and finance issues delayed plans to replace the bridge.