Samuel O’Reilly patented the tattoo gun in 1891

Tattoos, explained

Tattoos last because immune cells trap ink beneath the skin—but there's more to the story. This overview looks at how ancient cultures used tattoos for status, spirituality and punishment; how technology like the electric tattoo machine transformed the art form, and where innovations like smart tattoos could take it next.

Technological breakthroughs are spurring innovations in the industry

What if you could see your tattoos before they’re embedded in your skin? Or take a virtual visit into a local studio to work out your nerves over a first tattoo? The industry is anticipating some big technological changes, from 3D designs to sci-fi upgrades to more precise tattoo guns.

Rune Elmqvist forwent practicing medicine to invent the first inkjet printer

The Mingograph recorded real-time physiological signals from a patient's electrocardiogram, helping doctors diagnose heart and brain conditions. Eight years later, in 1958, Elmqvist worked with cardiac surgeon Åke Senning to develop the first fully implantable pacemaker.

'Magic ink' is redefining the tattoo

One University of Colorado professor has developed an ink that can be "turned on" with exposure to UV light, and "turned off" with sunlight. While the ink could help those who want to hide their body art from family members or coworkers, there are potential uses for medical procedures.

Tattoo inks are largely unregulated by the FDA

With hundreds of ink manufacturers, all unregulated by the FDA, it’s hard to determine the exact ingredients in tattoo inks. Some pigments may contain carcinogenic chemicals, such as heavy metals and aromatic hydrocarbons, or even bacterial contaminants. Red ink often causes allergic reactions and may even contain lead or mercury.

Credit for inventing the laser was fought over for nearly three decades

Although Theodore Maiman built the first working laser in 1960, Gordon Gould coined the term earlier. Charles Townes and Arthur Schawlow of Bell Labs filed a patent after Gould came up with the idea and name, but before Gould filed his patent.

The first 3D printing patent was filed in 1967

Wyn Swainson, an English literature graduate student, filed a patent in Denmark for a system that scans an object and uses the scanning data to rebuild it using lasers that harden light-sensitive plastic. However, he never developed a working prototype. The idea originated from wanting to produce recreations of sculptures.

Edward Jenner, the father of vaccinations

The British physician was the first to attempt to inoculate someone from smallpox using its milder cousin, cowpox. His innovations and documentations would prove crucial to the deployment of widespread vaccinations.

The treadmill was invented as a machine for prison labor

William Cubitt invented the machine in the early 1800s, imagining prisoners, usually two at a time, would use it to grind grain or pump water.

Thomas Edison inadvertently spurred the film industry's move to Hollywood

The inventor's patent on the motion picture camera included several stipulations that required independent movie studios to work with Edison's Motion Picture Patents Co., making the East Coast undesirable for aspiring filmmakers.

Photography was invented by a romantic artist

The invention of photography changed the landscape of art forever. The first photographs were created by Louis-Jacques-Mandé Daguerre, a romantic era printmaker, by using light and chemistry to expand upon images produced by the earlier camera obscura.

Tattoos remain visible on your skin thanks to immune cells called macrophages

Nail art can be traced back to 5,000 BCE

Archaeologists discovered Egyptian mummies with nail art and henna-tinted fingertips. The trend would continue informally for centuries until Revlon introduced modern nail polish in 1932.

Explore a gallery of electric vehicles from before 1920

In 1884, Thomas Parker invented the first practical electric car in London. By the turn of the century, early EVs were seen on the streets of Washington, DC. Automaker promotional materials included photographs of cars on mountain roads and other terrains.

Modern roll-on deodorant design was modeled on the ballpoint pen

Instead of a messy cream, which had been the norm in the 1940s, a new roll-on deodorant inspired by the easy flow of a ballpoint pen debuted in 1952.

Exactly who coined the term 'swimmer's ear' remains unknown

There is no record of anyone being the first person to call otitis externa by its most commonly known name, swimmer's ear. The earliest known use of the term was in a 1917 news article, according to the Oxford English Dictionary. The article in Connecticut's The Day stated that the illness was appearing among swimmers and bathers that summer.

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

When bamboo in China was tossed into fire in 200 BCE, there was an explosion. About 1000 years later, around 800 CE, an alchemist searching for secrets to immortality mixed sulfur, charcoal, and potassium nitrate together, leading to gunpowder. That mixture was then packed into bamboo or paper tubes, leading to fireworks.

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

Twain invented a clasp that's still used for bras

In 1871, Twain patented an “improvement in adjustable and detachable straps for garments.” Although he intended it for “vests, pantaloons, or other garments requiring straps,” it’s mostly used today in brassieres.

He was one of the first writers to cover surfing

For his 1872 travelogue “Roughing It”, Mark Twain visited Hawaii and described a then-peculiar sport: surfing. He even recalls his own attempts to catch a wave, writing, “I got the board placed right, and at the right moment, too; but missed the connection myself. The board struck the shore in three-quarters of a second, without any cargo, and I struck the bottom about the same time, with a couple of barrels of water in me.”

'Many of life's failures are people who did not realize how close they were to success when they gave up.'

- Inventor Thomas Edison (1847 - 1931)

Irish music became popular in the US during the 19th century

The influx of Irish immigrants in the mid-1800s, driven by starvation and abysmal employment opportunities, led to a significant Irish-American culture, especially in urban hubs such as New York, Boston, Philadelphia, Chicago, and San Francisco.

Surgery before the dawn of anesthesia

The arc toward anesthetics was painfully slow, with early pain mitigation offerings ranging from analgesics—drugs that dim pain but don't block it—and numbing surgical sites with cold water to gassing patients with carbon dioxide or bashing or bleeding them unconscious. Such treatments and the torturous surgery they preceded led many to avoid even life-saving procedures, and those who survived often kept silent about the trauma.

The popular myth behind the India pale ale

Legend has it that the beer style earned its name in the late 1700s and early 1800s, when one brewer realized he had to add more alcohol and hops to his beers to survive the long boat ride to India. But as this essay by one beer historian makes clear, the facts don't line up with that myth.

Rockwell left high school to become an artist

He began taking art classes at 14, while still in high school, but by 1910, he left traditional schooling to focus on his training at the National Academy of Design. He transferred to the Art Students League soon after to study under Thomas Fogarty, who taught him the particulars of commercial illustration, and George Bridgman, who was known for anatomically precise portraits.

'Steamboat Willie' was inspired by 'The Jazz Singer'

Walt Disney was mesmerized by Al Jolson's "The Jazz Singer" and the way it used synchronized sound, which synced film with audio. He replicated that effect in “Steamboat Willie," producing the first animated film to do so.

The Oscar statue was created in 1927

The statue of the golden knight that Academy Award winners receive (aka the Oscar) might be nearly as recognizable as the winners themselves. Oscar was born when art director Cedric Gibbons sketched him out and handed him over to sculptor George Stanley to bring to life.

The first robot in literature may have been a 'mechanical man' in 1907's 'Ozma of Oz,' a book in L Frank Baum's 'Wizard of Oz' series.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

While the first exchange-traded fund (a 'basket' of different assets that can be bought and sold on a stock exchange) in the US only launched in 1993, the global ETF market has grown to more than $10T in the short time since.

Abraham Lincoln was almost assassinated weeks before his inauguration as he traveled from Illinois to DC through Baltimore in 1861; it took two independent claims for Lincoln to be convinced the threat was real

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

Salvador Dalí believed he was his own dead brother, who had died nine months before he was born

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.

Mark Twain spent decades feuding with the US Postal Service, convinced its costs and regulations were bureaucratic overreach.

Poison ivy's characteristic rash is caused by an allergic response to an oily compound in the plant called urushiol.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

Double world record holder Hunter Ewen helped conquer his fear of balloons, called globophobia, by training to win Guinness World Record titles for balloon inflation.

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.

'Grand Canyon of the Yellowstone,' a work by American painter Thomas Moran, inspired Congress to establish Yellowstone National Park.

About 2,000 US babies are born annually without some portion of their limbs, potentially leading to a lifetime of pricey prosthetics.

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

Sony set the standard for cylinder-shaped batteries when it repurposed manufacturing equipment used to make rolls of magnetic recording tape.

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

When a Paris department store hesitated to sell Estée Lauder's perfume, she 'accidentally' broke a bottle, causing the smell to spread throughout the store and shoppers to start asking to buy the scent.

The power and influence of the American presidency have expanded significantly over time—far beyond what the founders envisioned.

The Ramones' 'Pet Sematary,' the theme song for the Stephen King novel of the same name, was written while the band was admiring the writer's collection of horror memorabilia.

Astronauts have repaired genetic damage in space using CRISPR—a molecular tool that can make precise changes to DNA and is used in single-celled organisms to attack invasive viruses.

See the evolution of Ebola vaccine and treatment development.

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