Although his actual birthday was January 15, American icon Martin Luther King, Jr., celebrates it today like few others - with a national holiday in his name.
A clergyman, activist, and leader in the quest for racial equality in the U.S., he was best known for civil rights advocacy using nonviolent civil disobedience.
He would have been 84 this month. MLK Jr. was killed by an assassin in 1969 at the age of just 39, but his legacy has endured, even grown in death.
President Lyndon Johnson would not have signed the Civil Rights Acts of 1964 and 1968 - some of the most significant policy changes in history - were it not for MLK.
King won the Nobel Peace Prize in 1964. He was posthumously given the Presidential Medal of Freedom in 1977 and Congressional Gold Medal in 2004.
Martin Luther King, Jr. Day was established as a U.S. federal holiday in 1986; hundreds of streets in the U.S. have been renamed in his honor.
Today, MLK Day happens to fall on the same day as the second inauguration of the first African-American President of the United States, Barack Obama.
Somewhere, you'd have to think King is smiling at the progress he helped bring about over half a century, even if an enormous amount remains to be done.
This year also marks the 50th anniversary of King's most famous address, the "I Have a Dream" during the March on Washington, August 28, 1963.
Watch that moving, historical moment below: