#TeenieTuesday . May 18, 1917 marks the 100th anniversary of the Selective Service Act, signed into law by President Woodrow Wilson. On April 6, 1917, the United States formally joined World War I, with only 100,000 volunteer troops. The new Selective Service Act required all men from ages 21 to 30 to register with the Selective Service System. By the war’s end in November 1918, 24 million American men had registered for the draft, and of the 4.8 million American troops who served in World War I, more than half had been conscripted. 350,000 African Americans served with the American Expeditionary Force on the Western Front, doing so in segregated and inferior conditions while only being allowed to work support roles that did not see combat. 20 years later, Teenie Harris captured military portraits of African American soldiers departing from Pittsburgh during World War II. . Charles "Teenie" Harris, Portrait of man wearing U.S. military uniform in Harris Studio, c. 1945-1950