"On December 15, 1967, the Silver Bridge collapsed while it was choked with rush hour traffic, resulting in the deaths of 46 people. Investigation of the wreckage pointed to the cause of the collapse being the failure of a single eye-bar in a suspension chain, due to a small defect only 0.1 inches (2.54 mm) deep."

More: http://en.wikipedia.org/wiki/Silver_Bridge

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