Unseen Civil Rights photos 63-3720 May 10, 1963 Kingwalker Dr. Martin Luther King and Rev. Wyatt Tee Walker announce an agreement with Birmingham businesses to desegregate certain sevices and jobs ...

In 1980, Martin Luther King Sr. published the memoir Daddy King: An Autobiography, a work that provided new insight into his life—and the family world that created Martin Luther King Jr.

Martin Luther King Jr. sits for his for police mugshot after his arrest for directing a boycott of segregated buses, Feb. 24, 1956, in Montgomery, Alabama. The LIFE Images Collection/Getty Images 9.

With his son Martin Luther III standing next to him, King pulls up a cross that had been burned on the front lawn of his home in April 1960. Bettmann Archive/Getty Images ...

Dr. Martin Luther King Jr., center, leads the dignity march on behalf of striking sanitation workers March 28, 1968. Rev. Henry Starks (right) clears the way for Dr. King and Rev. Ralph Abernathy ...

Rev. Martin Luther King Jr. made history as a defining leader of the Civil Rights movement who preached a message of nonviolent resistance. His hand in organizing a number of significant protests ...

Civil Rights activist Rev Dr Martin Luther King Jr. and his wife Coretta, daughter Yolanda, 5, & Martin Luther III, 3, sitting together as they play piano in their livingroom, Atlanta, Georgia, 1960.

Martin Luther King Jr. and Coretta Scott King laugh during entertainment at the St. Jude Hospital in Montgomery the night before the march to the Capitol, 1965.

The words "I Have a Dream" are historically famous. They defined the late civil rights leader Martin Luther King. But they're just one speech in a long life of brilliance and introspection.

As the country prepares to observe Martin Luther King day on Monday, Jan. 15, here's a look back at 10 of the most tweeted MLK quotes: 1. "The time is always right to do what is right." ...