Valentine's Day's namesake is unclear

The dark origins of Valentine's Day.

The holiday began as a feast to celebrate the decapitation of a third-century Christian martyr, or perhaps two. So how did it become all about love?

Some believe Valentine's Day evolved from the Roman holiday Lupercalia

The festival, which took place in mid-February, featured Roman priests sacrificing a goat and using its hide to lightly slap women and the land, believing it would bring fertility. Some believe that the Catholic Church repurposed the pagan holiday as a Christian one by attaching it to a saint, but scholars are not certain that this is true.

Check out Valentine's Day traditions from around the world

Valentine's Day is a holiday all about romance, but the way that's expressed differs depending on where the celebration takes place. This list breaks down some interesting takes on the holiday from across the globe, including mass weddings in the Philippines and Japan's gender-specific chocolate exchanges.

The St. Valentine's Day massacre is still unsolved

On Feb. 14, 1929, several men believed to be working for Chicago gangster George "Bugs" Moran, an enemy of notorious mobster Al Capone, were killed by several gunmen dressed as police. No one was ever brought to trial for the murders.

The average person celebrating Valentine's Day spends $189

That might include dinner, flowers, or something even more romantic. The most popular gift is candy, with 56% of people celebrating the holiday by purchasing sweets. That's about $2.5B in sales.

Poet Geoffrey Chaucer inspired the modern, romantic version of Valentine's Day

In the 1380s, the "Canterbury Tales" author wrote "The Parliament of Fowls," a 700-line poem about birds that choose their mates on St. Valentine's Day. The poem argued that romantic love—for fowls and humans alike—was an ideal, and linked the holiday with that sentiment.

The names of the 12 months are (mostly) derived from the Romans

January is named after two-faced Janus, February stems from a festival known as Februa, March comes from the god of war, Mars, and so on. Learn the origins and see ancient statues or art for the inspiration for each name of the month.

'Roses are red, violets are blue' has a long, twisting history

The earliest known use of the phrase, a stock romance form used in greeting cards, is in Edmund Spenser's "The Faery Queen" from 1590 (excerpt below). By 1785, Joseph Ritson updated the verse and connected it to Valentine's Day, creating a cliché that's still used today.

19th-century 'vinegar valentines' sometimes mocked recipients

In Victorian England, cards were sent to paramours and crushes, but they were also sometimes sent to people the sender disliked and would belittle them for their occupations or appearances. It was also expected that anyone who received a Valentine's Day card would send one in return, so there was a subgenre of responses, including rejections for unwanted suitors.

See a collection of Valentine's Day cards from the past century

Hallmark helped popularize (and commercialize) the holiday in the early 20th century, largely through its greeting cards. This digital collection includes cards from the 1910s through the 2000s, allowing you to see how the holiday—and our popular understanding of romance—has evolved. Below is a card from the 1930s.

Advertisers emphasized Cupid's childlike qualities to appeal to a younger demographic

Cupid is the Roman god of desire, and was often depicted in ancient mythology as both childlike and violent. In the 1800s, however, American advertisers eager to appeal to a younger demographic leaned into the less threatening versioning, portraying him as a cherubic child.

Six 'Vestal Virgins' kept the fire burning at Vesta's temple in Rome

Ancient Rome's Vestal Virgins were priestesses of the goddess Vesta and keepers of her eternal flame, tasked with keeping the sacred torch lit as a symbol of Rome's endurance. Children from well-connected aristocratic families would be selected for the role for decades of their lives.

A scholarly analysis of romance's enduring popularity

Diane Winston, a media scholar at the University of Southern California, argues that romance novels have remained popular because they've historically offered women shame-free ways to explore their identities and sexualities. She notes that's even more true today, with contemporary romance novels, from romantasy bestsellers to "Heated Rivalry," more willingly explore social dynamics.

George Washington's birthday was a federal holiday until it was moved to the third Monday in February in 1968

Washington's February 22 birthday became a federal holiday in 1879. A 1968 law moved it to the third Monday in February, and decades of advertising popularized the unofficial name "Presidents' Day," which the federal government never formally adopted.

Hear the story of Saint Nicholas, the inspiration for modern Santa Claus

A fourth-century Greek bishop in Turkey, Nicholas was known for his generosity and gift-giving. Legend holds that he secretly tossed gold bags through a window to save three sisters from slavery, which landed in stockings drying by the fire.

'Coral Castle,' Florida's self-built monument to a lost valentine

Latvian Ed Leedskalnin moved to the US shortly after his teenage fiancée ditched him. He quickly began work building a romantic tribute to this tragic episode via massive oolitic limestone. Working mostly at night, the Latvian cultivated an air of mystique as bystanders grew curious over his methods. Today, the castle stands as a bittersweet monument to unrequited love.

Early Christians viewed the Resurrection as a political claim about authority

Titles like "Son of God," "Lord," and "Savior" were in active circulation as official imperial titles at the time, stamped on Roman coins and carved into public inscriptions about Caesar. Early Christians applied those same words to Jesus, a crucified Jew, as a counter-claim about who actually held authority over the world. (Romans who refused to say "Caesar is Lord" were executed for it.)

An in-depth history of Guy Fawkes and the Gunpowder Plot

Guy Fawkes Day has been celebrated on November 5 in the United Kingdom for over four centuries, with bonfires, fireworks, and effigies. But who was Guy Fawkes, really? Learn about the Catholic radical who was a member of a group of 13 men eventually executed for their attempts to blow up Parliament and the king.

Easter is an uncommon name for Pascha, from the Hebrew 'pesach'

It's often said Easter is derived from pagan rituals. The word "Easter" does stem from a Germanic term for "dawn," but most cultural names for the holiday more clearly point to its Jewish history in the Passover.

There are several theories for how the Oscar got its name

Several different people claim to have bestowed the famous nickname, including a librarian who thought the knight resembled her uncle Oscar and a gossip columnist who was poking fun at a local theater owner.

No one's sure why it's spelled 'sundae'

There are several different folktales explaining the origins of the popular ice cream dish and its curious name. One claims an enterprising pharmacy used chocolate syrup instead of soda, which was banned on Sundays. Another claims the dish's unique spelling was to avoid offending religious folks who might object to an unholy reference to the Sabbath.

The name Visa was conceived by the company's founder, Dee Hock.

Visa was previously called National BankAmericard Inc. (NBI), but as other banks began to license the network and it expanded internationally, it needed a name less associated with both Bank of America and America itself. Hock believed that the word "Visa" implied no national identification and was relatively easy to pronounce in any language.

A thousand medieval dog names

In the Middle Ages, hunting was more than a sport—it was a vocation. Hounds were a crucial element of hunting, and wealthy landowners owned hundreds of them. A scribe in the late 15th century recorded more than 1,000 authentic names given to dogs, prompting a historian to speculate this showed just how well dog-handlers knew their animals. See the names here.

Robert Browning memorialized the marathon myth in a 19th-century poem

The story of Pheidippides is not likely true, but that hasn’t stopped the story from spreading. Much of that is thanks to Robert Browning, who enshrined the myth for a new generation in a 1879 poem that described the man dying after delivering word of the victory.

Explore real-life events linked to Friday the 13th

Though no statistics support the idea that Friday the 13th is more unlucky than other dates, the myth persists. See a grim collection of unfortunate events that occurred on the date throughout history.

The identity of the Tank Man in the iconic photo from the 1989 Tiananmen Square protests remains unknown and was possibly killed.

Learn more about the history of fireworks, which dates back to an accidental invention during an alchemist's quest for information about immortality.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

The concept of phantom limbs, the perception that amputated limbs are still present, dates back to a French military surgeon in the 16th century.

The name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto

During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted, leading authorities to suspect he was conspiring with the Russians.

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

Many legends about George Washington, including his supposed wooden teeth and the story of cutting down the cherry tree, lack evidence.

Georgia O'Keeffe's flower paintings are often assumed to be sexual, though the artist claimed she was simply interested in highlighting the beauty of flowers that most people neglect

El Niño, Spanish for 'the boy,' was named after Jesus Christ because the phenomenon resembled the weather changes observed around Christmastime.

Marburg virus, related to Ebola, is also extremely deadly, and has no available vaccine.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Meet the 56 signers of the Declaration of Independence—most of whom didn't put pen to paper until August 2, 1776—and see their original signatures.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

SpongeBob exemplifies Aristotle's philosophy for living well because he understands that happiness doesn't come from external factors like money, recognition, or power.

One disco producer saw 'Star Wars' four times on its opening weekend and was so inspired that he recorded the album 'Star Wars and Other Intergalactic Funk,' which produced a chart-topping single.

See a ranking of the best (and worst) Federal Reserve Chairs since 1914 out of the 16 men and women who have held the office since.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

In preparation for this weekend's Eurovision finale, which is something like the World Cup of pop music, here's a young Céline Dion performing (for Switzerland?) at the 1988 competition.

Domino's Pizza's 30-minute delivery guarantee was responsible for the chain's 1980s surge, but it was discontinued after the company was found liable for delivery driver accidents.