Martin Luther King Jr. Day, a federal holiday designated as a national day of service to encourage all Americans to volunteer and improve their communities, according to the National Museum of African American History and Culture.

Martin Luther King Jr. Day is always celebrated on the third Monday in January. It also happens to be Inauguration Day, which is always held on January 20th per the U.S. Constitution. The two typically don’t coincide, but they just so happen to fall on the same day this year.