The following is from Wikipedia:
Lunch atop a Skyscraper (New York Construction Workers Lunching on a Crossbeam) is a famous photograph taken by Charles C. Ebbets during construction of the GE Building at Rockefeller Center in 1932.
The photograph depicts 11 men eating lunch, seated on a girder with their feet dangling hundreds of feet above the New York City streets. Ebbets took the photo on September 29, 1932, and it appeared in the New York Herald Tribune in its Sunday photo supplement on October 2. Taken on the 69th floor of the GE Building during the last several months of construction, the photo Resting on a Girder shows the same workers napping on the beam.
The copyright owner of the photograph, the Bettman Archive, did not recognize Charles C. Ebbets as the photographer until October 2003 (reportedly after months of investigation by a private investigation firm).[1] Many posters and prints of the photograph continue to list the artist as ‘unknown.’