PHOTOS: On Martin Luther King Jr's birthday, a look at some of his rare vintage pics

Civil rights leader Martin Luther King Jr. sits in a cell at the Jefferson County Jail in Alabama, November 3, 1967.

(Original Caption) 6/22/62 Washington, D.C.: President Kennedy held a special White House conference with a group of white and Negro civil rights leaders. They gave the President a pledge of support, but said they will continue massive demonstrations. Posing in the Rose Garden (L to R) are: Martin Luther King, Jr., leader of the Southern Christian Leadership Conference; Attorney General Robert Kennedy; Roy Wilkins, Executive Secretary of NAACP; and Vice President Lyndon B. Johnson. (ORIGINAL CAPTION)

MONTGOMERY, AL - MAY 1956: Civil rights leader Reverend Martin Luther King, Jr. relaxes at home with his family in May 1956 in Montgomery, Alabama. (Photo by Michael Ochs Archives/Getty Images)

Martin Luther King Jr., gives his "I Have a Dream" speech to a crowd before the Lincoln Memorial during the Freedom March in Washington, DC, on August 28, 1963. The widely quoted speech became one of his most famous.

American Civil Rights leader Dr. Martin Luther King Jr. (1929 - 1968) speaks at a rally held at the Robert Taylor Houses in Chicago, Illinois, 1960s. (Photo by Robert Abbott Sengstacke/Getty Images)

MONTGOMERY- MARCH 25: Dr. Martin Luther King, Jr. seen close from the rear, speaking in front of 25,000 civil rights marchers, at the conclusion of the Selma to Montgomery march in front of Alabama state capital building on March 25, 1965. In Montgomery, Alabama. (Photo by Stephen Somerstein/Getty Images)