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Perhaps, among other things, the Tacoma Narrows Bridge

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was the most spectacular Aeolian harp in history.

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Unfortunately, its first performance was destined to run only about four months.

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In the meantime, she was a beautiful bridge.

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Beautiful, but a little strange.

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Even before construction was completed, people observed its peculiar behavior.

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That was because, even in a light breeze, ripples ran along the bridge.

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After a while, one of the local humorists called her Galloping Gertie.

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And for fairly obvious reasons, the name stuck, at least until the 7th of November, 1940.

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Then as now, Seattle and Tacoma were sports-minded cities.

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For four months, a regional sport was to drive across the bridge on a windy day.

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While some claimed it was like riding a roller coaster, others found it a little disconcerting

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to see the car in front disappear.

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How popular this bridge sport was, or to what extent it might have spread across the country,

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is anybody's guess.

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On November 7, 1940, the winds were relatively moderate, about 40 miles per hour.

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A new mode appeared.

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Rather than ripple, the bridge began to twist.

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The wind of 40 miles per hour is not too strong, but it was strong enough to start the bridge

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twisting violently.

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11 a.m., it fell.

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Investigators were mystified.

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A bridge constructed according to the best engineering standards of the day.

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Perhaps the best bridge in the world.

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This was not a bridge that was supposed to collapse.

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What in the world had happened?

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Theodore von Karman, a Caltech professor and a pioneer in modern aerodynamics, came forth with the answer.

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Von Karman's explanation of vortex shedding and resonant oscillations

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was not universally popular among construction engineers.

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However, as verified by wind tunnel tests at Caltech and at the University of Washington,