This gem from the Prelinger Archive documents the construction of the San Francisco-Oakland Bay Bridge, which was completed in 1936. Produced by U.S. Steel, it celebrates the engineering of the structure, one of the largest in the world at the time, and the people who built it. Skip to about 8:50 to see nonchalant workmen jumping up and down on terrifying mesh catwalks suspended high above the bay. 

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