Boiler shop crew, U.S. Navy Yard, Mare Island, California

By an unknown photographer, 1901

The Navy Yard at Mare Island, near Vallejo, California, was once the largest industrial plant west of the Mississippi. Between 1854 and 1996, when the yard closed, workers built several generations of U.S. Navy ships there. Boilermakers, like those pictured above, built, installed, and repaired boilers that generated the steam needed to drive huge ship turbines.

National Archives–Pacific Region (San Bruno), Records of Naval Districts and Shore Establishments