A look at historical ciphers, from the Spartan 'scytale' to the Navajo Code Talkers

The science of cryptography, including methods to encrypt data and how to break encryption

Monoalphabetic ciphers use a set of rules to replace each letter with another consistently, making them susceptible to brute force attacks that try every kind of replacement. While more complex ciphers can transform text in less obvious ways, because certain letters are used more often than others, an analysis of letter frequency may reveal patterns that help uncover the rules that make up a cipher.

The story of Kryptos, the long unsolved cryptographic sculpture outside the CIA's headquarters

Made by American artist Jim Sanborn, the sculpture features four copper plates engraved with messages written with the 26 letters of the Latin alphabet and question marks. The last of these plates was solved in 2025, but the piece remains of interest to cryptoanalysts.

The history and operation of SIGABA, the US counterpart of the Nazi Enigma machine

Developed by the US Army and US Navy, over 10,000 of these machines were deployed by the end of World War II to encrypt messages for the armed forces using three series of rotors. The device would continue to be used until the 1950s, while personal computers were shown to possess enough computing power to crack it by 2021.

Archaeologists decode the first known sentence in what may be the oldest written alphabet

This five-minute video details the accidental discovery and subsequent decoding of the first known sentence in what's believed to be the oldest written alphabet. The Canaanite sentence was found on a Bronze Age hair comb unearthed in Tel Lachish, a city of the ancient Biblical Kingdom of Judah, during a dig focused on excavating the kingdom's first Iron Age city. The Canaanite language developed sometime between 3,000 and 1,000 BCE.

How the Inca used threads to communicate

One of the great mysteries of ancient Peru is that the Inca did not have a system of writing, but communicated with a system of strings tied with knots. This 4-minute video explores its possible uses.

Cacao is a Maya word that survives today

In the 1980s, archaeologists finally deciphered Maya hieroglyphs in part by identifying known words. Maya scholar David Stuart notes that cacao—still used today—was one of the key linguistic anchors that unlocked ancient Maya texts.

The long-lost art of coded postage stamps

In the 1800s, the postcard was a relatively new phenomenon, as was the post office. In the burgeoning system, recipients of mail had to sometimes pay prohibitively costly fees to receive it. So to get around the fees, a system of placing stamps on the envelopes in specific ways to communicate—a simple yes or no—was devised by clever mailers and expanded and codified by postcard companies into guides. Learn about the fascinating system here.

Indigenous women crafted the integrated circuits for the Apollo Guidance Computer

Applying their blanket-weaving skills, over 1,000 Navajo women in New Mexico were hired to connect circuit components in intricate patterns using a microscope. Outside Boston, "rope mothers" at the Raytheon facility wove the AGC's core memory using threaded metal wires.

Medieval sword manuals survive—but their techniques are hard to decode

While some knights guarded their combat knowledge, others recorded it in illustrated fighting manuals. Centuries later, scholars struggle to interpret these cryptic texts, revealing how much medieval martial knowledge was lost or obscured over time.

Sequoyah single-handedly invented a writing system for the Cherokee language

Without formal education, Cherokee citizen Sequoyah spent more than a decade in the early 1800s developing an 86-character syllabary—a writing system in which each symbol represents a spoken syllable—for the Cherokee language. Within a few years, most Cherokees could read and write it.

Ancient Romans sometimes lobbed insults through graffiti

Graffiti was used to communicate ideas, offer advice, and, not unlike the internet, talk some trash. That was especially true with tourists, who sometimes scrawled messages on the pyramids, including one person who complained, "I can not read the hierogylphics." In response, someone replied, "Why do you care that you can not read the hieroglyphics? I do not understand your concern."

Ancient ghost stories appeared in texts like 'The Odyssey'

Sharing ghost tales has been around for centuries. Ancient Mesopotamia, Rome, and Greece each had their own chilling stories about encountering spirits. Find mentions of specters in some of history’s most famous writings like the "Epic of Gilgamesh" and "The Odyssey."

Unraveling the charred remains of the only known library from antiquity

This article details the quest to decipher the charred remains of a library buried during Mt. Vesuvius' volcanic blast. In 1752, nearly 2,000 papyrus scrolls were found in Herculaneum. According to this article, this collection is the only complete library that has survived from antiquity. In the last decade, scientists have made strides in decoding the crumbling texts.

Chess traces its roots to chaturanga in sixth-century India

The earliest form of chess, known as chaturanga, emerged in India around the sixth century. The game simulated four divisions of the military—infantry, cavalry, elephants, and chariots—and laid the foundation for modern chess’ structure and strategy.

The Greeks named their dogs with short names similar to modern ones

Xenophon, a historian from ancient Greece, proposed that the best dog names were limited to one or two syllables and referenced important qualities, like courage or speed. Some ideas: Aura, meaning "breeze," or Corax, a raven.

Pre-coin currencies like shells were subject to counterfeiting

While it is difficult to pinpoint the very earliest form of money that was used, a type of shell called cowrie shells were used as currency as far back as 3300–2000 BCE. These shells were imitated using ivory, bone, clam shells and more.

Contactless credit cards descend from a batteryless Cold War listening device

The same physics that let Soviet spies eavesdrop on the US ambassador in 1945 underlie contactless payment methods today. The device is a passive chip powered wirelessly by incoming radio waves.

The Antikythera mechanism is the oldest example of an analog computer

Remains of the 2,000-year-old hand-powered model of the solar system were uncovered in a shipwreck off the coast of Greece in 1900. It had been used to calculate the motions of the sun, moon, and planets to help forecast events such as solar eclipses.

Memes can be traced back to the chain letter

Such intentional reshaping of communication transmissions dates back at least hundreds of years to the advent of the chain letter, a type of message that asks readers to create their own copy or at least forward it to others.

Graffiti dates back to at least ancient Pompeii, where citizens scrawled messages to one another on public walls

DNA cassette tapes could store 36,000 terabytes of data

By translating binary code into the base-pair code found in genetic sequences, researchers in China are storing digital data on DNA-coated tapes for compact, durable, and energy-efficient storage. The tapes use a blend of polyester and nylon with barcode patterns for data addressing.

Decoding sports-betting language

The world of sports gambling is filled with insider lingo: What's a "spread"? How about a "moneyline" or a "parlay"? This resource breaks down the jargon, helping you navigate the industry or, at least, giving you the keys to talk about it.

Onion routing disguises internet traffic in layers resembling a nesting doll

Data is encrypted at least three times before being sent to a node—a server that can only decrypt one layer. Then, the underlying encrypted data is relayed to another node, and the process repeats until all layers are decrypted. Thousands of possible nodes make it extremely difficult to trace activity within the system.

The Greek island of Sfyria's dying whistling language

Sfyria is a whistled version of modern Greek native to a corner of Euboea, the second largest island of Greece, and is used for long-distance communication. Its name derives from the Greek word sfyrizo, meaning to whistle. The language's practitioners are fighting to preserve its use and legacy, as it is one of the world's most endangered. Learn more about their fight in this article.

The history of skull modification

The ancient Maya people sometimes modified their skulls to appear more conical. Body modification has been a human pastime for literal ages, from piercings to bindings and everything in between. Modifying one's skull shape may have been a way to symbolize status, beauty, belonging, or belief. The health impacts of such practices are still debated. This article explores the history and health impacts of skull modification, also known as artificial cranial deformation.

Sailor tattoos represent naval milestones

Sailors often come home with mermaids or turtles adorning their bodies. But what does it mean to have permanent images of propellers on your bum, British galleons with soaring tiers of sails on your chest, or a bicep portrait of the Roman god Neptune? Those tattoos represent meaningful naval milestones.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

English mathematician Ada Lovelace wrote the first computer algorithm a century before computers existed and hypothesized that computing devices would one day be able to compose music—foreseeing the generative AI systems of today.

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.

The original copy of the Declaration of Independence is not a pristine document, and even features a smudged anonymous handprint in the bottom left corner.

The idea for the Federal Reserve was conceived in secret in 1910—with bankers donning duck hunt gear for disguise while traveling to a remote country club on Georgia's Jekyll Island

American short story writer Flannery O'Connor raised 40 peacocks, which became potent symbols for her fiction's elegant violence

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

In 2019, a laptop loaded with six of the worst malware in history and described as 'an exhibit of historical weaponry' sold for $1.3M.

Search a massive database of over 4 decades of clues from the TV quiz show 'Jeopardy!'

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight

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.

See how fireworks are made and learn how metals like magnesium and copper are responsible for different colors.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

Explore an interactive map of battles from the American Revolution, along with detailed summaries of each engagement

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

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

Lesser-known phobias include turophobia, or the fear of cheese, and nomophobia, the fear of being without your cell phone.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

Ebola is a filovirus, meaning it resembles a thread under a microscope, though it sometimes twists and can resemble a bowl of spaghetti.

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

Waves off the coast of Nazaré, Portugal, can reach over 100 feet and are caused by the area's deep underwater canyon geography

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.