April Fools' Day or All Fools' Day is a day celebrated in many countries on April 1st. The day is named for the custom of playing practical jokes and hoaxes of varying sophistication on friends, family members, enemies, and neighbours, or sending them on a fool's errand, the aim of which is to embarrass the gullible. Traditionally, in some countries, such as the UK, Australia and South Africa the jokes only last until noon, and someone who plays a trick after noon is called an "April Fool". Elsewhere, such as in Canada, France, Ireland, Italy, Russia, The Netherlands, and the U.S., the jokes last all day.
Though it has been observed for centuries in several countries, including France and Britain, its origin is unknown. It resembles the Hilaria festival of ancient Rome (March 25th) and the Holi festival of India (ending March 31st). The custom of playing April Fools' jokes was brought to America by the British.
In Spain and Ibero-America, an equivalent date is December 28th, Christian day of celebration of the Massacre of the Innocents. The Christian celebration is a holiday in its own right, a religious one, but the tradition of pranks not, though the latter is observed yearly. After somebody plays a joke or a prank (such as sticking paper cut-outs of little men, or Monigotes to people’s backs) on somebody else, the joker usually cries out, as a popular expression, "¡Inocente!" (Innocent!).