According to Wikipedia - Memorial Day is a federal holiday in the United States for mourning the U.S. military personnel who died while serving in the United States Armed Forces.  It is observed on the last Monday of May. It is also considered to be the unofficial beginning of summer.  Memorial Day is a time for visiting cemeteries and memorials to mourn the military personnel who died in the line of duty. Volunteers will place American flags on the graves of those military personnel in national cemeteries.  The first national observance of what would become Memorial Day occurred on May 30, 1868.  Then known as Decoration Day, the holiday was proclaimed by Commander-in-Chief John A. Logan of the Grand Army of the Republic – a fraternal organization of veterans – to honor Union soldiers who had died in the American Civil War.  This national observance followed the example of many local observances which were begun between the end of the Civil War and Logan's declaration. Many cities and people have claimed to be the first to observe it, however, the National Cemetery Administration, a division of the Department of Veterans Affairs, credits Mary Ann Williams of the Ladies Memorial Association of Columbus, Georgia, with originating the idea of an annual date to decorate the graves of Civil War veterans with flowers.  Official recognition as a holiday spread among the states, beginning with New York in 1873.  By 1890, every union state had adopted it. The world wars turned it into a day of remembrance for all members of the U.S. military who fought and died in service. In 1968, Congress changed its observance to the last Monday in May, and in 1971 standardized its name as "Memorial Day.” Two other days celebrate those who have served or are serving in the U.S. military: Armed Forces Day, which is earlier in May, a ceremonial U.S. day of commemoration for honoring those currently serving in the armed forces, and Veterans Day on November 11, a legal holiday which honors all those who have served in the United States Armed Forces.