Dr. Martib Luther King Jr.: Pledging to carry on his mission, thousands mark 50th anniversary of Martin Luther King Jr.'s death - by Jenny Jarvie

In an echo of King's visit to Memphis in 1968, scores of men on Wednesday carried black-and-white signs identical to ones carried that year by striking sanitation workers: "I AM A MAN."

Many who rallied outside the American Federation of State, County and Municipal Employees Local Union 1733 headquarters on Beale Street early Wednesday were sanitation workers whose strike for better working conditions inspired King to come to Memphis.

King was fatally wounded on April 4, 1968, as he stood on a balcony of the Lorraine Motel, which is now part of the National Civil Rights Museum. Jesse Jackson, the 76-year-old civil rights activist who is one of the last living witnesses of King's assassination, stood on the balcony Wednesday.

"The balcony does not have the last word," he said. "We would not let one bullet kill a movement."

At the King Center in Atlanta, Bernice King, the slain civil rights leader's youngest daughter, said, "Now more than ever before, we need his teachings, his principles, his steps of nonviolence."

The King Center presented its highest award, the C Peace Prize, to social activist and lawyer Bryan Stevenson and Benjamin Ferencz, a prosecutor at the Nuremberg trials of Nazis after World War II.

PHOTOS: A nation remembers Martin Luther King Jr. »

Among those who remembered King on Wednesday was Rep. John Lewis (D-Ga.), who spoke in Indianapolis, where Sen. Robert F. Kennedy announced news of King's death during a presidential campaign rally. "I have bad news for you, for all of our fellow citizens, and people who love peace all over the world, and that is that Martin Luther King was shot and killed tonight," Kennedy told the crowd that evening.

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