The custom of honoring ancestors by cleaning cemeteries and decorating graves is an ancient and worldwide tradition, but the specific origin of Memorial Day, or Decoration Day as it was first known, are unclear. In early rural America, this duty was usually performed in late summer and was an occasion for family reunions and picnics. After the Civil War, America's need for a secular, patriotic ceremony to honor its military dead became prominent, as monuments to fallen soldiers were erected and dedicated, and ceremonies centering on the decoration of soldiers' graves were held in towns and cities throughout the nation. No less than 25 places have been named in connection with the origin of Memorial Day, and for many years, states observed the holiday on different dates. By federal law, however, Memorial Day is now celebrated on the last Monday in May. Since it all started with the Civil War, you might want to brush up on your knowledge of this event by visiting the Library of Congress Civil War collection, which includes more than a thousand photographs.