The Martin Luther King Jr. Memorial and cherry blossom trees are seen on the Tidal Basin in Washington in 2012. MLK Jr. Day falls on Jan. 19 this year. Reuters

Martin Luther King Jr. Day is Monday, giving Americans a three-day weekend to reflect on civil rights as well as honor the leader of the movement. But how much do you know about the man behind the holiday?

Everyone has heard at least part of the "I Have A Dream" speech, which King gave at the historic March on Washington in August 1963. You might know he was born on Jan. 15 (he would have been 86 this year), and that he's the only non-president to have a national U.S. holiday dedicated to him. Maybe you're aware he was Time magazine's Man of the Year in 1963 and authored five books. But instead of parroting these facts to your friends on Monday, try starting a deeper conversation. Here are nine little-known facts about Martin Luther King Jr.:

1. At birth, his parents actually named him Michael King Jr. His dad changed his name five years later after visiting Germany and being inspired by images and stories about the 16th century priest Martin Luther, according to the History Channel.

2. King skipped ninth and 11th grade. As a result, he went to Morehouse College at age 15.

3. His house -- with his wife and daughter inside -- was bombed on Jan. 30, 1956, according to CNN. "Don't get panicky," King told the crowd outside once he got there. "If you have weapons, take them home ... We must meet hate with love."

4. He was arrested in 1963 for organizing a march in Birmingham, Alabama. That's where his famous essay "Letter from Birmingham Jail" came from. You can read its full text here.

5. King had several extramarital affairs, and the FBI knew about them. The organization sent him a threatening letter in 1964, calling him "a complete fraud," according to Yahoo News.

6. King was fatally shot April 4, 1968, on the balcony of the Lorraine Motel in Memphis, Tennessee. He was out there secretly smoking, and when his colleague Billy Kyles saw King was shot, he took the cigarette out of his hand so nobody would find out he smoked.

7. The motel owner's wife happened to see the assassination and had a heart attack immediately after, according to Mental Floss.

8. Martin Luther King Jr. Day was signed into law by former President Ronald Reagan in 1983, but not all states recognized it until 2000. Utah was the last holdout.

9. James Earl Ray was sentenced to 99 years in prison for allegedly killing King. He died of hepatitis C in 1998.