April Fool's Day is celebrated on April 1st with jokes and pranks. It originated in France where April 1st was previously considered the new year, until the pope changed the new year date. Traditional April Fool's pranks include sending people on "fool's errands" with false instructions or placing paper fish on their back and yelling "Poisson d'Avril" when discovered. In the US, the day is marked by playing jokes on others and saying "April Fools!" afterwards.