Memorial Day is a federal holiday in the United States for mourning the U.S. military personnel who have died while serving in the United States armed forces. It is observed on the last
Monday of
May at national cemeteries, by placing flowers and American flags on graves of military personnel. By the late 1800s, many more cities and communities observed Memorial Day, and several states had declared it a
legal holiday. After World War I, it became an occasion for honoring those who died in all of
America's wars and was then more widely established as a national holiday throughout the United States.