Martin Luther King Jr., a reverend and civil-rights activist, was assassinated at 39. However, he inspired several movements and political changes.

Government offices are closed for the holiday, while several museums offer free entry and special programming to honor the civil rights leader.

The holiday falls on the third Monday of January. A bill to make Martin Luther King Jr. Day a federal holiday was introduced on April 8, 1968 — four days after King was assassinated, according to the National Museum of African American History and Culture.