The April 2, 1698 edition of Dawks’s News-Letter reported that “Yesterday being the first of April, several persons were sent to the Tower Ditch to see the Lions washed.” This is the first recorded instance of a popular April Fool's Day prank that involved sending people to the Tower of London to see the "washing of the lions." The joke was that there was no lion-washing ceremony. It was a fool's errand. (For more info, see the Hoaxipedia article: Washing The Lions)