Preaching a message of nonviolent resistance, the Rev. Martin Luther King Jr. was the leading ... here’s a look back at his defining years in pictures.

"They said I had 25,000, and he had a million people, and I'm okay with it because I liked Dr. Martin Luther King." That clip ...

To look back on the historic day further, view the photos below. FILE - The Rev. Dr. Martin Luther King Jr., head of the Southern Christian Leadership Conference, speaks to thousands during his "I ...