Memorial Day is a federal holiday in the United States observed on the last Monday of May. It honors and remembers the men and women who have died in military service for the country. The holiday originated after the American Civil War to decorate the graves of fallen soldiers, and was later expanded to honor those who died in all American wars. It is traditionally seen as the start of the summer season and is marked by visiting cemeteries and memorials, flying the American flag at half-staff, and various cultural events.