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The Rev. Martin Luther King Jr. waved to supporters on the Mall during the "March on Washington" on Aug. 28, 1963.

AP/File

King delivered his "I Have a Dream" speech at the rally.

AP File

King acknowledged the crowd at the Lincoln Memorial.

AP File

Demonstrators gathered at the Washington Monument grounds, before marching to the Lincoln Memorial.

AP File

King (center left, with arms raised) marched along Constitution Avenue with other civil rights protesters.

AP File

The rally on the National Mall would become the defining civil rights gathering in the United States.

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Civil Rights leaders posed in the Lincoln Memorial during the "March on Washington."

Cecil Stoughton/White House/John Fitzgerald Kennedy Library, Boston

King (third from left) and other civil rights leaders met with President John F. Kennedy at the White House.