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

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

Some coin denominations have ridges on their sides in part to prevent counterfeiting

You may have noticed that dimes and quarters feature small ridges on their sides that other coins, like pennies and nickels, don't have. This video can help you learn more about why the practice, called "reeding," was first started—and why it's still used today.

The designs on US coins have changed a lot over the years

From states producing and issuing their own coins after the Revolutionary War, to collectors’ coins in modern times, US coins have had many design changes throughout history. You can learn about the different variations, plus what design elements are added to all US coins today, in an article.

Thomas and Anne Rogers were famous counterfeiters in 17th-century England

The pair used a practice called “coin clipping,” shaving the edges off silver coins to decrease their weight before sending them back into circulation. When banknotes rather than coins gained popularity, counterfeiting methods evolved—in the 1700s, an early banknote counterfeiter named Mary Butterworth created counterfeit paper money using starched cloth and a hot iron to transfer the pattern of a banknote onto paper.

‘Mint marks’ are tiny letters on US coins that correspond to which mint location created them

As more mint branches opened up after Philadelphia (the first mint location), these “mint marks” helped hold each branch responsible for the quality of the coin. A coin minted in Philadelphia, for instance, would have the letter “P” on it. Some mint marks are extremely rare, making coins displaying them particularly valuable to collectors.

Every printed bill has its own unique serial number

In the US, each bill also has its own plate number, series year, Treasury seal, and more. Each design helps track money and combat counterfeiting.

The platinum coin, explained by the creator of the idea

An obscure US Mint law permitting it to create platinum coins of any amount surfaced as a possible means of quickly paying down the national debt. Here's an explanation from the creator of the idea.

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.

The Secret Service was originally formed to combat counterfeiting

By the 1860s, an estimated one-third of US currency in circulation was counterfeit. In 1865, the Secret Service was created specifically to combat the country's serious counterfeiting problem, which had led to widespread financial instability. This was partly due to the lack of federal currency standardization in the country at the time.

Chip technology replaced magstripes to stop easy card cloning and fraud

The magstripe on bank cards always gives the same data, making it simple to copy using a device called a grabber. In contrast, embedded chips create a unique code with every transaction, making it much harder to clone or steal card information.

The Australian $5 bill has an image of a bird that glows when exposed to UV light

That’s just one of the many anti-counterfeiting security measures that the Australian government implements on its currency. Popular banknotes from around the world all include their own unique security features—this infographic outlines a few unique ones.

A startup is trying to create the diamond equivalent of the gold standard

It's called the Diamond Standard Co, and it uses an algorithm to assign standard values to a variety off small diamonds, grouping them together into individual coins. Historically, diamonds haven't been able to be classified as commodities or standardized like gold because they aren't uniform—factors such as clarity, cut, color, and carat size significantly influence the value of a diamond.

One of the Widow Clicquot’s many innovations was the process of riddling

Riddling involves storing Champagne bottles at an angle and methodically turning them in order to collect any sediment in the neck of the bottle. The technique—which was kept a strict secret—cut down on both time and waste, allowing the House of Clicquot to outsell its competitors for decades until word inevitably leaked and riddling became the standard.

See a collection of ancient Roman coins used on the Silk Roads

As ancient Rome's appetite for eastern luxuries grew, long-distance trade routes linking the Mediterranean to Asia emerged along what became known as the Silk Road. Without shared language or legal systems, merchants could use the reliable Roman coins to exchange with other cultures. This exhibit features gold and silver pieces bearing the portraits of emperors and Latin inscriptions.

Specific imperfections are needed to make Swiss cheese

Impurities in the milk are critical for the formation of holes in Emmental. The cleanliness at farms today could potentially eliminate the iconic characteristic, though cheesemakers are finding a solution to preserve the holes that help define the cheese.

Crypto history's is full of bizarre stories

Digital currencies based solely on misspellings of former President Joe Biden’s name have skyrocketed, and backers of a token based on a Shiba Inu wearing a hat raised $690K to get their logo on the Las Vegas Sphere.

Colored paint lines on new tires mark different types in the factory

Each stripe helps warehouse workers and distributors identify tire types at a quick glance. This innovation became important a century ago as manufacturers scaled operations and developed distinct product lines.

Peruse a running sale of collectible checks

The George H. Labarre galleries hold regular auctions of collectible checks, along with other numismatic items (such as coins, paper money, and so on). See the antiquated iconography on old checks from railroads, regional banks, and businesses.

When Niagara Falls stopped flowing

In 1969, engineers stopped Niagara Falls for the first time in 12,000 years to prevent erosion revealing hidden coins, boulders, and a rare dry view before restoring its roa

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.

A look at nodes and miners in managing bitcoin transactions

Each time a transaction involving bitcoin is carried out, the information must be relayed and recorded onto the currency’s blockchain. Multiple steps are involved, including the passage of the transaction to various nodes and miners who comprise multiple layers of verification and validation. See an illustrated guide to how these two crucial features of bitcoin processing work here.

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.

Roy Lichtenstein popularized benday dots in his famous comic-inspired paintings

American newspaper publisher Benjamin Henry Day Jr. developed the "benday" printing and photoengraving technique to produce grays and colors with fine patterns of ink of equal size and distribution. The process would become widespread in newspaper printing and define the work of Roy Lichtenstein.

Not all companies with bank-sounding names are actually FDIC-insured banks

When purchasing a certificate of deposit, it's important to know if you are purchasing a “deposit” product issued by an FDIC-insured bank.

Paying a fee to delay paying back a loan in full is called 'rolling over' the loan

Borrowers sometimes roll over loans when they aren't able to pay back the full principal balance and accrued interest. A rollover extends the amount of time the borrower has to repay the loan, but does not decrease the amount of money the borrower has to pay back.

Mid-ocean ridges are underwater volcano systems where tectonic plates diverge

New ocean crust is formed at these ridges as magma rises from Earth’s mantle and fills the space between the spreading plates. The speed of divergence influences ridge shape, with slow spreads forming rugged valleys and fast spreading creating smooth, wide slopes.

Was the stone that sealed Jesus's tomb round or square?

Archaeologist Amos Kloner's survey of more than 900 Second Temple-era burial caves found only four with round, disk-shaped stones—all belonging to the very wealthy. The other 98-plus percent used square, cork-shaped stones, suggesting the popular image of a wheel rolled away from Jesus's tomb is probably a later artistic invention. The Greek verb translated as "rolled" can also mean "moved."

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 US dollar is the most widely circulated currency in the world, and is involved in nearly 90% of global transactions

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

Explore fun facts from the USPS, including unique post office buildings, a stamp that traveled past Pluto, and more.

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.

The term 'algorithm' originated from the Latinized name of al-Khwārizmī, a 9th-century mathematician whose works introduced Arabic numerals and the decimal-based numeral system to Europe and whose treatise 'Al-Jabr' gave algebra its name.

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

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

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.

Corals are themselves not coral reefs—the term refers to the tiny marine invertebrates that build the rigid reef.

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.

Ebola species have historically been named after where they were discovered, stigmatizing residents who live there, including Bundibugyo, in Uganda.

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.

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.

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.

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

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

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

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.

See photos of Meteora, a mountainous site in central Greece, home to 14th-century monasteries perched atop soaring outcroppings.

Prince's sexually explicit 1984 track 'Darling Nikki' attracted the ire of the Parents Music Resource Center, an advocacy group that inspired the Parental Advisory sticker, even though the song ends with a Christian message.