The Santos Inocentes, Holy Innocents´ day, is a celebration in which people play jokes and pranks on each other in Spain.
Spain's Christmas celebrations begin on December 22nd, when the big lottery draw of El Gordo (lit. the Fat One) takes place, and lasts until January 6th, the day Los Tres Reyes Magos bring presents for the kids. But Spain, being the country of fiestas, makes room for one more celebration between Christmas Eve and New Year's Eve. This celebration is called El Dia de los Santos Inocentes or “Holy Innocents' Day”, and it is a day in which everyone young and old becomes wary that they may be the innocent soul that gets duped by friends.
The history behind el Día de los Santos Inocentes is religious and based on the Bible story of when King Herod heard the news that a new King of Israel was born (Jesus), he immediately ordered the massacre of all boys under the age of two in Bethlehem and its vicinity. The name given to this day, Día de los Santos Inocentes or “Day of the Holy Innocents”, fits perfectly well due to the many innocent souls that were lost that night.