From France to Iceland to the United States, April Fools’ Day is celebrated with practical jokes and elaborate hoaxes.

Wondering why April 1 is all about jokes and hoaxes? Here’s a deep dive into the strange history and uncertain origins of April Fools’ Day, from calendar mix-ups to medieval pranks.

April Fools' Day is celebrated worldwide, and many countries have their own unique pranks and jokes. In France, paper fish are often put on someone's back as a joke because the fish are said to be young and, therefore, easily caught. The prank is called the "April Fish," and those who get the fish placed on their backs are seen as gullible.