Everyone knows the photograph of workmen taking their lunch while perched on a girder high above New York City. Taken in 1932, it remains one of the most iconic images of the twentieth century. Every time I look at it an instant fear of heights resonates within me. A lunchbreak 850 feet above the ground? Only if I'm seated at a table and safely behind a window enjoying the view!

But, I've always wondered about the story behind the photograph. Who are these daredevils and who took...