Memorial Day in the United States honors the men and women who have died while serving in the U.S. military. Originally called Decoration Day, it was established after the Civil War to commemorate Union and Confederate soldiers who lost their lives. By the late 19th century, it evolved into a national holiday observed on the last Monday of May. On this day, Americans visit cemeteries and memorials, decorating graves with flags and flowers. Memorial Day serves not only as a remembrance of military sacrifice but also as a time for reflection on the costs of freedom and national service.