The first day of April is a day to be wary. Also known as April Fool’s Day, it is the time to subject those around you to carefree practical jokes. Surprisingly, many countries around the world observe the holiday, each one slightly different from the others. While it’s origin is a bit of a mystery, multiple theories have been proposed. The most popular explanation involves the change from the Julian to Gregorian calendar during the 1500’s. Since the Julian calendar’s new year begins on Mar. 25, with festivals following in the beginning of April, many people were initially confused by the switch to Jan. 1. Some would attempt to trick friends and neighbors into thinking that Apr. 1 was still the day to celebrate the new year. To this day, many around the world continue the custom of pranks and shenanigans.

UK: In the UK, April Fool’s Day only lasts until noon. Those who continue to pull pranks after midday will bring bad luck upon themselves. Conversely, those who are unable to tolerate the jokes made at their expense will also be unlucky.

France: Victims of practical jokes are known as “poisson d’avril”, or April fish. This is a reference to young fish born in springtime, which makes them easy to catch. Many pranks pulled tie into the fish theme, a traditional one being to tape a paper fish onto someone’s back to indicate their gullibility.

Iran: The Persian new year usually lands on Apr. 1 or 2. Known as Sizdah Bedar, celebrators gather on the streets to picnic and play scary tricks on one another. Another custom is to throw away green vegetables, called sabzeh, to throw away bad luck before the new year.

India: In India, the Hindu Holi Festival rings in the coming of spring, symbolic of the defeat of evil. Taking place on Mar. 31 and spanning two days, revelers throw water and colored powder on each other, as well as partake in lighthearted pranks.

These are just a handful of the many ways people around the world commemorate this lively holiday. So let loose, and maybe try out a couple of clever tricks on your friends!