13 Facts About Friday the 13th

Stockbyte/iStock via Getty Images
Stockbyte/iStock via Getty Images

There are plenty of superstitions out there, but none have woven themselves into the fabric of our culture quite like Friday the 13th. It's inspired books, songs, and one of the most successful horror movie franchises of all time. But despite giving us anxiety, the origins of this notorious date on the calendar remain largely unknown to most. Where did it start? Does it really stretch back to the 14th century? And how does Loki figure into all of it?

There are a lot of urban legends and half-truths out there, so we're diving a bit deeper into the history of this most terrifying of days with 13 facts about Friday the 13th.

1. The Bible helped inspire the phobia.

The Last Supper
iStock

Part of superstition surrounding Friday the 13th comes from the Christian Bible. During the Last Supper, there were 13 guests—Jesus and his 12 apostles, one of which, Judas, would eventually betray him. Since then, some have believed in a superstition regarding 13 guests at a dinner table. This slowly extended to be an overall feeling that the number itself was bad luck.

Of course, when Jesus was crucified, it took place on a Friday, leading some to view the day with an anxious eye. Taken separately, both the number 13 and Friday have since made their way into modern superstitions.

2. So did Loki.

Guided by Loki, Höðr shoots the mistletoe at Baldr.
Guided by Loki, Höðr shoots the mistletoe at Baldr.
Wilhelm Wägner, Wikimedia Commons // Public Domain

The Last Supper is one view on the origins of our fear of 13. Another comes from Norse mythology—more specifically in the form of the trickster god Loki. In those stories, Loki tricked the blind god Höðr into killing his brother Baldr with a dart of mistletoe. Baldr's mother, Frigg, had previously ordered everything in existence to never harm her son, except the mistletoe, which she viewed as incapable of harm.

How does 13 figure into this? Some accounts say Baldr's death took place at a dinner held for 12 gods before it was interrupted by Loki—the 13th (and most unwanted) guest.

3. Some point to the Knights Templar as the source of why people fear the day (but it's probably not true).

Jacques de Molay, the 23rd and Last Grand Master of the Knights Templar, is lead to the stake to burn for heresy in 1314.
Jacques de Molay, the 23rd and Last Grand Master of the Knights Templar, is lead to the stake to burn for heresy in 1314.
Hulton Archive, Getty Images

Contrary to what The Da Vinci Code told you, the reason people fear Friday the 13th isn't because of the Knights Templar. On the very unlucky Friday, October 13, 1307, Philip IV of France had members of the Templar arrested—growing uneasy with their power and covetous of their riches. There were trials, torture, and many of the Knights were burned at the stake, eventually leading to the superstition of Friday the 13th as a cursed and evil day.

That's not quite true, though. This is a take that's been drummed up in recent years, most visibly in Dan Brown's best-selling novel, but in reality, the unlucky combination of Friday and 13 didn't appear until around the turn of the 20th century.

4. A 1907 novel played a big part in creating the superstition.

Panic on 'Black Friday' in the New York Gold Room, 1869.
Three Lions, Getty Images

We know a good deal about the history of our fear of 13 and of Fridays, but combined? Well, that's less clear. One popular thought, though, points to a 1907 book by a stockbroker named Thomas Lawson. Titled Friday, the Thirteenth, it tells the tale of a stockbroker who picks that particular day to manipulate the stock market and bring all of Wall Street down.

The book sold fairly well at the time, moving 28,000 copies in its first week. And it must have struck a chord with early 20th century society, as it's said to have caused a real-life superstition among stockbrokers regarding trading and buying stocks on the 13th. While not the first to combine the dates, Lawson's book is credited with popularizing the notion that Friday the 13th is bad news.

The fear among brokers was so real that in a 1923 New York Times article, it stated that people "would no more buy or sell a share of stock today than they would walk under a ladder or kick a black cat out of their path."

5. Stockbrokers have reason to be nervous on Friday the 13th.

The 1873 rush from the New York Stock Exchange as banks began to fail and close, leading to a 10-day closure of the Stock Exchange.
Three Lions, Getty Images

Lawson's book was pure fiction, but the history of the stock market on Friday the 13th can be either profitable or absolutely terrifying, depending on the month. On most Friday the 13ths, stocks have actually risen—according to Time, they go up about 57 percent of the time, compared to the 52 percent on any other given date. However, if it's a Friday the 13th in October … be warned.

There's an average S&P drop of about 0.5 percent on those unlucky Fridays in October. And on Friday, October 13, 1989, the S&P actually saw a drop of 6.1 percent—to this day, it's still referred to as a "mini crash."

6. Good things happen on Friday the 13th, too!

Hollywood sign on the hill
iStock

On Friday, July 13, 1923, the United States got a brand new landmark as the famed Hollywood sign was officially christened as a promotional tool for a new housing development. But before the sign took on its familiar image, it initially read "Hollywoodland"—the full name of the development that was being built on the hills above Los Angeles. The sign took on its current “Hollywood” look in 1949 when, after two decades of disrepair, the Hollywood Chamber of Commerce decided to remove the last four letters and just maintain the first nine.

7. Appropriately, heavy metal music was born on Friday the 13th.

Cover of Black Sabbath album
vinylmeister, Flickr // CC BY-NC 2.0

This one isn't exactly scientific, but don't tell that to a metalhead. According to heavy metal lore, the genre was born Friday, February 13, 1970, with the UK release of Black Sabbath's self-titled debut album. Bands like Steppenwolf had laid the foundation in the years before (Steppenwolf is also credited with coining the term "heavy metal" in their lyrics for 1968's "Born to Be Wild"), but those first dissonant "Devil's Tritone" chords of "Black Sabbath"—yes, the opening track of the album Black Sabbath by the band Black Sabbath was the song "Black Sabbath"—were the true birth of the dark, brooding, rocking subculture. Horns up.

8. There are scientific terms for the phobia.

Friday the 13th on a calendar
iStock

Afraid of Friday the 13th? Well now you can put a name to your phobia. You likely already know the term triskaidekaphobia, which only applies to the fear of the number 13. But for specific fears of Friday the 13th, you can choose between paraskevidekatriaphobia (Paraskevi meaning Friday in Greek) or friggatriskaidekaphobia, based on the word Frigg, the Norse goddess that Friday was named after in English. (Remember, it was her son who Loki had killed …)

9. One Indiana town puts bells on every black cat to ward off bad luck.

Black cat wearing a bell.
Danilo Urbina, Flickr // CC BY NC-ND 2.0

The folks of French Lick, Indiana (Larry Bird's hometown) are apparently a superstitious lot. In the 1930s and extending into the '40s, the town board decreed all black cats in the town were to wear a bell around their neck every Friday the 13th. Apparently, the confluence of two popular phobias was a bit too much for the small Indiana town to handle.

10. Five presidents were part of a club to improve the number's reputation.

old-fashioned formal dinner
iStock

Some people aren't just unaffected by the stigma of 13, they're downright defiant of it. In order to prove that there was no curse on the number, Captain William Fowler—who had fought in 13 Civil War battles—started a club in 1882 that spat in the face of superstition.

Members would meet on the 13th of the month, at 13 past the hour, and sit 13 at a dining table. For some, this behavior was just begging for a hex, but these men didn't care. They sought to disprove the myth and others along with it—open umbrellas lined the dining hall and members would willingly break glass, waiting for a so-called curse to befall them.

This wasn't just a club for eccentrics, either. Five presidents would become honorary members of The Thirteen Club: Chester Arthur, Grover Cleveland, Benjamin Harrison, William McKinley, and Theodore Roosevelt. In fact, Cleveland would take part while he was in office. In all, it's said that no man was struck down by any particularly curious fate (except perhaps McKinley, who was assassinated), despite having so blatantly tempted it.

11. In Italy, people fear Friday the 17th.

number 17 on a wooden background
iStock

Italy's got the right idea, but they're a few days off. Traditionally, their fear coincides with the number 17, which can be arranged as the sum of the Roman numerals VIXI, which can then, in turn, be translated as the Latin phrase "I have lived." The overall superstition around Friday remains the same—it all has to do with Jesus's crucifixion.

This is no niche phobia, though. As ThoughtCo. points out, there are people who refuse to leave the house or go to work on Friday the 17th out of fear of the ominous date. And the Italian airline Alitalia doesn't even put a row 17 (or a 13) on its planes, as seen on this seat map [PDF].

12. There can't be more than three Friday the 13ths in a given year.

Calendar of 2015 with three Friday the 13ths
Calendar: iStock. Coloring: Mental Floss.

There's some good news if you're one of those people who are genuinely afraid of Friday the 13th: There can't be more than three in any given year, and it's possible to go as many as 14 months without one. There's an easy way to figure out if a month will have a Friday the 13th, too—if the month starts on a Sunday, you're guaranteed one. For 2018, 2019, and 2020, we get a bit of a break, as each year will only have two. This year, only April and July are affected.

13. An asteroid will come relatively close to us on a Friday the 13th in 2029.

asteroid projection image
iStock

Let's just get this out of the way: We'll be fine. An asteroid will not collide with the Earth on Friday, April 13, 2029. We will, however, get a pretty spectacular look at asteroid 99942 Apophis (also known as 2004 MN4), which is about 320 meters wide and would be devastating if it did hit. When the asteroid was first discovered in 2004, astronomers gave it a haunting 1-in-60 chance of colliding with Earth, but extra data has proved that it'll miss us entirely.

"We weren't too worried," Paul Chodas, of NASA's Near Earth Object Program, said, "but the odds were disturbing."

That's not to say the asteroid still won't be a sight to behold: Apophis will cruise past Earth 18,600 miles above ground. "For comparison," NASA wrote on its site, "geosynchronous satellites orbit at 22,300 miles." The asteroid will be mostly visible in parts of Asia, Africa, and Europe, and another event of this nature may not be seen for another 1000 or so years.

Looking to Downsize? You Can Buy a 5-Room DIY Cabin on Amazon for Less Than $33,000

Five rooms of one's own.
Five rooms of one's own.
Allwood/Amazon

If you’ve already mastered DIY houses for birds and dogs, maybe it’s time you built one for yourself.

As Simplemost reports, there are a number of house kits that you can order on Amazon, and the Allwood Avalon Cabin Kit is one of the quaintest—and, at $32,990, most affordable—options. The 540-square-foot structure has enough space for a kitchen, a bathroom, a bedroom, and a sitting room—and there’s an additional 218-square-foot loft with the potential to be the coziest reading nook of all time.

You can opt for three larger rooms if you're willing to skip the kitchen and bathroom.Allwood/Amazon

The construction process might not be a great idea for someone who’s never picked up a hammer, but you don’t need an architectural degree to tackle it. Step-by-step instructions and all materials are included, so it’s a little like a high-level IKEA project. According to the Amazon listing, it takes two adults about a week to complete. Since the Nordic wood walls are reinforced with steel rods, the house can withstand winds up to 120 mph, and you can pay an extra $1000 to upgrade from double-glass windows and doors to triple-glass for added fortification.

Sadly, the cool ceiling lamp is not included.Allwood/Amazon

Though everything you need for the shell of the house comes in the kit, you will need to purchase whatever goes inside it: toilet, shower, sink, stove, insulation, and all other furnishings. You can also customize the blueprint to fit your own plans for the space; maybe, for example, you’re going to use the house as a small event venue, and you’d rather have two or three large, airy rooms and no kitchen or bedroom.

Intrigued? Find out more here.

[h/t Simplemost]

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

10 Facts About Real Genius On Its 35th Anniversary

Val Kilmer stars in Martha Coolidge's Real Genius (1985).
Val Kilmer stars in Martha Coolidge's Real Genius (1985).
Sony Pictures Home Entertainment

In an era where nerd is a nickname given by and to people who have pretty much any passing interest in popular culture, it’s hard to imagine the way old-school nerds—people with serious and socially-debilitating obsessions—were once ostracized. Computers, progressive rock, and role-playing games (among a handful of other 1970s- early '80s developments) created a path from which far too many of the lonely, awkward, and conventionally undateable would never return. But in the 1980s, movies transformed these oddballs into underdogs and antiheroes, pitting them against attractive, moneyed, successful adversaries for the fate of handsome boys and pretty girls, cushy jobs, and first-place trophies.

The 1985 film Real Genius ranked first among equals from that decade for its stellar cast, sensitive direction, and genuine nerd bona fides. Perhaps fittingly, it sometimes feels overshadowed, and even forgotten, next to broader, bawdier (and certainly now, more problematic) films from the era like Revenge of the Nerds and Weird Science. But director Martha Coolidge delivered a classic slobs-versus-snobs adventure that manages to view the academically gifted and socially maladjusted with a greater degree of understanding and compassion while still delivering plenty of good-natured humor.

As the movie commemorates its 35th anniversary, we're looking back at the little details and painstaking efforts that make it such an enduring portrait not just of ‘80s comedy, but of nerdom itself.

1. Producer Brian Grazer wanted Valley Girl director Martha Coolidge to direct Real Genius. She wasn’t sure she wanted to.

Following the commercial success of 1984’s Revenge of the Nerds, there was an influx of bawdy scripts that played upon the same idea, and Real Genius was one of them. In 2011, Coolidge told Kickin’ It Old School that the original script for Real Genius "had a lot of penis and scatological jokes," and she wasn't interested in directing a raunchy Nerds knock-off. So producer Brian Grazer enlisted PJ Torokvei (SCTV) and writing partners Babaloo Mandel and Lowell Ganz (Splash, City Slickers) to refine the original screenplay, and then gave Coolidge herself an opportunity to polish it before production started. “Brian's original goal, and mine, was to make a film that focused on nerds as heroes," Coolidge said. "It was ahead of its time."

2. Martha Coolidge’s priority was getting the science in Real Genius right—or at least as right as possible.

In the film, ambitious professor Jerry Hathaway (William Atherton) recruits high-achieving students at the fictional Pacific Technical University (inspired by Caltech) to design and build a laser capable of hitting a human-sized target from space. Coolidge researched the subject thoroughly, working with academic, scientific, and military technicians to ensure that as many of the script and story's elements were correct. Moreover, she ensured that the dialogue would hold up to some scrutiny, even if building a laser of the film’s dimensions wasn’t realistic (and still isn’t today).

3. One element of Real Genius that Martha Coolidge didn’t base on real events turned out to be truer than expected.

From the beginning, the idea that students were actively being exploited by their teacher to develop government technology was always fictional. But Coolidge learned that art and life share more in common than she knew at the time. “I have had so many letters since I made Real Genius from people who said, 'Yes, I was involved in a program and I didn’t realize I was developing weapons,'" she told Uproxx in 2015. “So it was a good guess and turned out to be quite accurate.”

4. Val Kilmer walked into his Real Genius audition already in character—and it nearly cost him the role.

After playing the lead in Top Secret!, Val Kilmer was firmly on Hollywood’s radar. But when he met Grazer at his audition for Real Genius, Kilmer decided to have some fun at the expense of the guy who would decide whether or not he’d get the part. "The character wasn't polite," Kilmer recalled to Entertainment Weekly in 1995. "So when I shook Grazer's hand and he said, 'Hi, I'm the producer,' I said, 'I'm sorry. You look like you're 12 years old. I like to work with men.'"

5. The filmmakers briefly considered using an actual “real genius” to star in Real Genius.

Among the performers considered to play Mitch, the wunderkind student who sets the movie’s story in motion, was a true genius who graduated college at 14 and was starting law school. Late in the casting process, they found their Mitch in Gabriel Jarrett, who becomes the third generation of overachievers (after Kilmer’s Chris and Jon Gries’s Lazlo Hollyfeld) whose talent Hathaway uses to further his own professional goals.

6. Real Genius's female lead inadvertently created a legacy for her character that would continue in animated form.

Michelle Meyrink, Gabriel Jarret, Val Kilmer, and Mark Kamiyama in Real Genius (1985).Sony Pictures Home Entertainment

Michelle Meyrink was a staple of a number of ‘80s comedies, including Revenge of the Nerds. Playing Jordan in Real Genius, she claims to “never sleep” and offers a delightful portrait of high-functioning attention-deficit disorder with a chipper, erratic personality. Disney’s Chip 'n Dale: Rescue Rangers co-creator Tad Stones has confirmed that her character went on to inspire the character of Gadget Hackwrench.

7. A Real Genius subplot, where a computer programmer is gaming a Frito-Lay contest, was based on real events.

In the film, Jon Gries (Napoleon Dynamite) plays Lazlo Hollyfeld, a reclusive genius from before Chris and Mitch’s time who lives in a bunker beneath their dorm creating entries to a contest with no restrictions where he eventually wins more than 30 percent of the prizes. In 1969, students from Caltech tried a similar tactic with Frito-Lay to game the odds. But in 1975, three computer programmers used an IBM to generate 1.2 million entries in a contest for McDonald’s, where they received 20 percent of the prizes (and a lot of complaints from customers) for their effort.

8. One of Real Genius's cast members went on to write another tribute to nerds a decade later.

Dean Devlin, who co-wrote Stargate and Independence Day with Roland Emmerich, plays Milton, another student at Pacific Tech who experiences a memorable meltdown in the rush up to finals.

9. The popcorn gag that ends Real Genius isn’t really possible, but they used real popcorn to simulate it.

At the end of the film, Chris and Mitch build a giant Jiffy Pop pack that the laser unleashes after they redirect its targeting system. The resulting popcorn fills Professor Hathaway’s house as an act of revenge. MythBusters took pains to recreate this gag in a number of ways, but quickly discovered that it wouldn’t work; even at scale, the popcorn just burns in the heat of a laser.

To pull off the scene in the film, Coolidge said that the production had people popping corn for six weeks of filming in order to get enough for the finale. After that, they had to build a house that they could manipulate with hydraulics so that the popcorn would “explode” out of every doorway and window.

10. Real Genius was the first movie to be promoted on the internet.

A week before Real Genius opened, promoters set up a press conference at a computer store in Westwood, California. Coolidge and members of the cast appeared to field questions from press from across the country—connected via CompuServe. Though the experience was evidently marred by technical problems (this was the mid-1980s, after all), the event marked the debut of what became the online roundtable junket.