Walter Gadsden, 17, defying an anti-parade ordinance of Birmingham, Ala., is attacked by a police dog on May 3, 1963. (Bill Hudson/Associated Press)
Firefighters use their water hose against civil rights demonstrators in Birmingham, Ala. on July 15, 1963. (Bill Hudson/Associated Press)
Police lead a group of black school children to jail after their arrest for protesting against racial discrimination near city hall in Birmingham, Ala. on May 4, 1963. (Bill Hudson/Associated Press)
Rev. Fred Shuttlesworth, center in hat, joins white passengers on a city bus in Birmingham, Ala., six days after the U.S. Supreme Court ruled that the buses must integrate on Dec. 26, 1956. Shuttlesworth boarded hours after a bomb exploded inside his Collegeville, Ala., house. (Robert Adams/The Birmingham News via Associated Press
American clergyman and civil rights campaigner Martin Luther King Jr. on May 23, 1961. (William Lovelace/Express/Getty Images)
US civil rights leader Martin Luther King Jr. waves from the steps of the Lincoln Memorial to supporters on the Mall in Washington, DC, during the "March on Washington" on Aug. 28, 1963. In 1963 King spoke in front of 250,000 people, explaining his wish for better relations between black and white Americans. His words were engraved on the steps of the monument where he spoke. (AFP/Getty Images)