It was first proposed four days after King's 1968 assassination outside a Memphis motel. It took 15 years until it became a federal holiday.

“With malice toward none, with charity for all, with firmness in the right, as God gives us to see the right, let us strive on to finish the work we are in, to bind up the nation’s wounds.” -- Abraham Lincoln, March 4, 1865.

Every year we honor the legacy of Martin Luther King Jr. in January. Here's everything you need to know about the holiday.