Why is April Fools' Day on April 1? What to know about the unofficial prank holiday

If you're not a fan of pranks, beware in advance: Friday is April Fools' Day.

The first day of April is regarded as the day to celebrate the unofficial holiday, where it is encouraged to play practical jokes, hoaxes or hijinks on others. It's also customary to yell "April Fools!"

In previous years, April 1 has also been a day where companies have teased pretend prank releases, from Velveeta delving into skincare to Green Giant cauliflower-flavored Peeps just in time for Easter.

So, where did April Fools' Day come from? And why do we celebrate it every year? Here's what you should know.

The origins of April Fools' Day

According to the History Channel, the origins of the holiday are not entirely known, but it was celebrated for several centuries by different cultures. It could be referenced as early as 1392 in the "Nun's Priest's Tale" from Geoffrey Chaucer's "The Canterbury Tales," although that's disputed.

The Christian world switched from the Julian calendar to the Gregorian calendar in the 16th century, which moved the New Year to January 1. According to Time, some historians believe April Fools' Day came from that switch, as people still using the Julian calendar were fooled by the new year date.

Ideas: 15 silly gag gifts for April Fools' Day

In Scotland, by the 18th century, it had become a two-day tradition. The first day was "hunting the gowk," (a cuckoo bird, or a symbol for a fool), where people were sent on fake errands. The second day was Tailie Day, where people typically pinned tails or signs on the back of the unsuspecting.

Is April Fools' Day a holiday?

April Fools' Day is not recognized as a holiday in any country except for Odessa, Ukraine, where April 1 is an official city holiday. It is not a federal holiday in the U.S., although the tradition of playing pranks and jokes still goes on.

Famous April Fools' Day pranks

Everyone, from companies to first lady Jill Biden have gotten in on the fun.

The Museum of Hoaxes ranked an April 1, 1957 segment from the BBC TV show "Panorama" as the number one April Fools' hoax of all time. During the show, broadcasters remarked on the Swiss spaghetti harvest, which they said was enjoying a bumper year. The segment even showed footage of Swiss peasants pulling spaghetti from trees, leading viewers to call the BBC, asking how to grow their own spaghetti trees.

In 1996, Taco Bell took out full-page ads in six major American newspapers, claiming it had bought the Liberty Bell "an effort to help the national debt." After thousands of worried people called Taco Bell headquarters and the National Park Service believing the purchase to be real, the Philadelphia branch of the NPS held a press conference where they assured people it had not been sold.

Eventually, Taco Bell admitted to the prank, and donated $50,000 to preserve the Liberty Bell.

Google has also had its fair share of pranks. coming up with a number of fake products including Google Romance, Gmail Paper, Google Translate for Pets and Google Gulp, a drink the company said in 2005 would help "to achieve maximum optimization of your soon-to-be-grateful cerebral cortex.”

This article originally appeared on Cincinnati Enquirer: Why do we celebrate April Fools' Day? What to know about the tradition