Made by an unknown press photographer, this photograph shows civil rights protesters John Lewis and John Zwerg in Montgomery, Alabama, after having been attacked for their participation in a Freedom Ride on May 20, 1961. Zwerg, at right, removes teeth knocked out by his attackers. The Freedom Rides were a series of nonviolent demonstrations in 1961. Volunteers called Freedom Riders rode in interstate buses to the segregated South to test the 1960 United States Supreme Court decision "Boynton v. Virginia," which outlawed racial segregation in interstate transportation facilities, including bus stations and railroad terminals.