It's April 1st, what does it mean?

Today is April 1st, the day most commonly called "April Fool's Day" and it's celebrated in many countries by people in the United States, Canada, the United Kingdom, France, Ireland, Italy, Japan, Russia, Australia, South Africa, The Netherlands and other countries around the world. 

 It's a day

to practice jokes and play fun pranks on people around you. 

Nobody is exactly sure where the tradition started but nowadays it's an excuse to play silly jokes on friends. 

As it happens at Catalonia on December 28th, many newspaper, radio personalities, television shows, and internet web sites participate in the celebration.