It’s an iconic image of the building of America: Eleven construction workers on a break for lunch, happily chatting away on a girder balanced some 800 feet above New York City. The photograph, taken during the construction of the RCA building (now the GE building) in Rockefeller Center, ran in the October 2, 1932 edition of the New York Herald. For all its enduring popularity (the image is frequently reprinted and has graced an abundance of posters, greeting cards and desktop backgrounds), little was known about its history until fairly recently. The photographer, Charles C. Ebbets, was not...