Martin Luther King Jr

"I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character.

I have a dream today."

On April 4, 1968, civil rights leader Martin Luther King Jr., 39, was shot to death as he stood on a balcony at the Lorraine Motel in Memphis, Tenn.; the killing sparked a wave of riots across the country.

Sen. Robert Kennedy breaks the news to supporters at a presidential campaign rally.