This Friday, be on the lookout for black cats crossing the road and a crazed killer in a hockey mask because it’s once again Friday the 13th, that unluckiest of days. Today will be the first time in 2016 when people will be fearing 24 hours of bad luck. Not everyone knows how Friday the 13th became an unlucky thing, so for those who don’t, here are six trivia facts about one of the freakiest days of the year.

One & Done In 2016

This Friday the 13th will be the only one in 2016. Those who fear the unlucky day won’t have to worry again until January 2017. Next year will also have an October Friday the 13th, right in the heart of Halloween season. 

Movie Franchise

One of the most popular horror-movie franchises was inspired by the date. There have been 12 “Friday the 13th” movies made, and The Wrap reported in October the 13th film is set to be released on Jan. 13, 2017, which is a Friday. The CW is also developing a TV series based on the movies, Bloody Disgusting reported in November.

13 Superstition

Part of the reason why some fear Friday the 13th is the unluckiness that’s associated with the number. There are a few reasons people believe the number brings bad fortune. According to History.com, mathematicians and scientists view 12 as a “perfect” number and some view the number 13 as “lacking.” There is also the idea that Judas was the 13th guest at the Last Supper in the Bible and Loki was the 13th guest at a dinner party with other gods in Norse myths.

Tuesday Is Also Unlucky

CNN reported in NOvember that Friday the 13th isn't the only day considered unlucky; in some Spanish-speaking countries, every Tuesday is, too. Tuesday is the day of the week that’s associated with Mars, the Roman god of war. Because of this, some believe people they shouldn’t do anything of significance on this day of the week.

Celebrities Born on Friday the 13th

Each year babies are born on Friday the 13th and many celebrities happen to have been born on the infamous date. Fox News Magazine reports Steve Buscemi, Julia Louis-Dreyfus, Darius Rucker, and Mary-Kate and Ashley Olsen all came into the world on the day.

Annual Tradition

While some years have more Friday the 13ths than others, at least one will occur in any given year. According to TimeandDate.com, the most that can occur in any calendar year is three, while the longest you can go without getting one is 14 months. Whenever a month begins on a Sunday, it’s a guarantee there will be a Friday the 13th.