This painting is a small version of a twenty-nine-foot mural Gropper painted for the U.S. Department of the Interior in Washington, D.C. It celebrates the activities of the department's Bureau of Reclamation, which in the mid-1930s supervised construction of Boulder, Grand Coulee, and other major dams in the western United States. Gropper's heroic, muscular workers harness nature with their strength, while the huge concrete structures celebrate the genius and audacity of American engineering.