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Martin Luther King Jr. leading the second Selma to Montgomery civil rights march in Selma, Alabama, on March 9, 1965.

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Leaders of the March on Washington for Jobs & Freedom link arms on Aug. 28, 1963. Among those pictured (front row from left): John Lewis, Matthew Ahman, Floyd B. McKissick, Dr. Martin Luther King Jr., Reverend Eugene Carson Blake, Cleveland Robinson, and Rabbi Joachim Prinz. The march provided the setting for King's iconic "I Have a Dream" speech.

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King surrounded by reporters during a public address in Birmingham, Alabama, in 1962.

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King during a press conference on Dec. 4, 1964, holding up photos of three young civil rights workers murdered in Mississippi.

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King shaking hands with the crowd during the Freedom March on Washington, 1963.

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