In this combination of Associated Press file photos, at top, civil rights protestors march down Constitution Avenue carrying placards during the March on Washington on Aug. 28, 1963; and at bottom, people rally at the Lincoln Memorial in Washington to commemorate the 50th anniversary of the 1963 march Saturday, Aug. 24, 2013. Dr. Martin Luther King Jr. delivered his "I Have a Dream" speech during the March on Washington on Aug. 28, 1963. (AP Photo/File)

In this combination of Associated Press file photos, at top, civil rights protestors march down Constitution Avenue carrying placards during the March on Washington on Aug. 28, 1963; and at bottom, people rally at the Lincoln Memorial in Washington to commemorate the 50th anniversary of the 1963 march Saturday, Aug. 24, 2013. Dr. Martin Luther King Jr. delivered his "I Have a Dream" speech during the March on Washington on Aug. 28, 1963. (AP Photo/File)