A U.S. Navy sailor poses on the stairway of a barracks building at Mare Island Naval Shipyard, California, in 1917 -- the year the United States entered World War I. Mare Island served as a key West Coast shipyard and training station, rapidly expanding to process the influx of new recruits. This informal snapshot, preserved in a personal photo album, reflects the everyday life of sailors far removed from posed studio portraiture. Project: 218551