Federal and state offices, banks, as well as postal and trash services will be closed or suspended Monday. Here’s what else you should know.

— Martin Luther King Jr.‘s “I Have a Dream” speech

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.

The U.S. is set to mark Martin Luther King Jr. Day, the federal holiday set aside to honor the life of the civil rights icon. But in two states, Monday is also Robert E. Lee Day in honor of the Confederate general.