While many Americans think of Memorial Day as the unofficial first day of summer, the holiday originated as a day to honor those who died in the Civil War.
General John Logan, commander of the Great Army of the Republic, selected May 30 as Decoration Day. He chose the date because no battles took place on that day.
After WWI, the holiday was adjusted to honor Americans who had died fighting in any war, not just the Civil War. It became a federal holiday in 1971, to be celebrated the last Monday in May.