New York Yankees star Babe Ruth (r) salutes Gen. John "Black Jack" Pershing on 28 May 1924. Ruth had just signed up for a three-year hitch with the New York National Guard, though he continued to play baseball full-time. Pershing was the leader of the U.S. expeditionary forces during World War I in 1917-18.
Photo from the National Photo Company Collection of the U.S. Library of Congress, Prints and Photographs Division. Image number npcc 11507