Memorial Day, which falls on the last Monday of May, honors the men and women who died while serving in the American military. Originally known as Decoration Day, it originated in the years following the Civil War and became an official federal holiday in 1971. Many Americans observe Memorial Day by visiting cemeteries or memorials, holding family gatherings and participating in parades. Unofficially, at least, it marks the beginning of summer. In 2011, Memorial Day is observed on Monday, May 30.