Memorial Day is a federal holiday in the United States for remembering the people who died while serving in the country's armed forces. The holiday, which is observed every year on the last Monday of May, was formerly known as Decoration Day and originated after the American Civil War to commemorate the Union and Confederate soldiers who died in the war. By the 20th century, Memorial Day had been extended to honor all Americans who died while in the military service. It typically marks the start of the summer vacation season, while Labor Day marks its end.
Many people visit cemeteries and memorials, particularly to honor those who have died in military service. Many volunteers place an American flag on each grave in national cemeteries.