Many Americans have the day off from work and school on Monday. The three-day weekend is seen as the unofficial start of the summer vacation season. Many families have picnics or make trips to beaches, parks or campgrounds.
Officially, Memorial Day, observed on the last Monday in May, has been set aside to honor all who died during military service throughout U.S. history. Congress declared Memorial Day a national federal holiday in 1971.
Observances around the country and in Washington are planned for the day. President Donald Trump will participate in a wreath-laying ceremony at the Tomb of the Unknown Soldier at Arlington National Cemetery.
Memorial Day began in 1865, just after the end of the Civil War. For more than 50 years, the holiday only remembered those killed in the Civil War. It was not until America's entry into World War One that the tradition was expanded to include those killed in all wars.
On Sunday, the event known as Rolling Thunder, involving thousands of war veterans and others on motorcycles, rolled into Washington as they do every year, passing the monuments on the National Mall, to honor U.S. soldiers missing in action in foreign wars.