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Seattle Underground City

Did you know the remnants of Seattle's original streets are still accessible? Beneath the bustling streets of modern-day Seattle lies the Underground City , a network of subterranean passageways that formed the ground level in the 1800s.

By the end of the 19th century, after the Great Seattle Fire, it was decided to rebuild the city at a higher elevation to combat frequent flooding . So, these original streets, sidewalks, and storefronts were buried, and with it, much of their history.

Guided tours take people through tunnels and ladders and retell real and eerie stories about the history of the Underground City.

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Luray Caverns

Image: Robert Thiemann

Have you ever heard of the underground Stalacpipe Organ ? Not only is it a one-of-a-kind interaction between keyboards and cavern stalactites, but it is also the largest musical instrument in the world, according to Guinness World Records.

This instrument lives in the Luray Caverns, Virginia. It consists of an electric console that taps on these ancient stalactites of varying sizes to produce musical tones. A subterranean wonder, these caverns are also known for their extraordinary size , housing towering stalactites and stalagmites, mirrored pools, and delicate drapery-like calcite formations.

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The Underground Gardens of Baldassare Forestiere

Image: Adrian Botica

This stunning subterranean retreat was built entirely by hand. Tucked under the sun-scorched landscape of Fresno, California, lie the Underground Gardens of Baldassare Forestiere . They are the life’s work of Baldassare Forestiere, a Sicilian immigrant who started digging in the early 1900s to escape the Central Valley's oppressive heat.

Over 40 years, drawing inspiration from ancient Roman catacombs , Forestiere carved an elaborate network of underground rooms, passageways, grottoes, and courtyards that span 10 acres.

A unique masterpiece, the gardens are open with guided tours that lead guests through beautifully designed spaces featuring skylights, arches, and alcoves. This oasis also boasts an array of fruit trees, including citrus, figs, and olives.

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Ruby Falls

Image: Goodfreephotos_com

Colorful and breathtaking, the Ruby Falls is a geological wonder located inside Lookout Mountain near Chattanooga, Tennessee.

Hidden over 1,000 feet below the mountain's surface, this waterfall cascades 145 feet into a pool , making it one of the tallest underground waterfalls open to the public.

Visitors enter the mountain and descend via elevator. Then, they walk through stunning cave formations such as stalactites, stalagmites, and flowstone. At the waterfall chamber, multicolored lights –powered by renewable energy– illuminate the falls. Lantern-lit tours are also offered as a chance to visit the marvel with a different charm.

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The Catacombs of Green-Wood Cemetery

Image: Joy Ernst

Arched tunnels of tranquil, sacred vaults lie beneath the Green-Wood Cemetery in Brooklyn, New York. Built in the mid-19th century, these catacombs were designed as a prestigious resting place for the city’s elite , prominent families.

While the catacombs are typically closed to the public, special events are sometimes organized to welcome visitors, such as art expositions, guided history tours, and candlelit tours seasoned with live music and storytelling.

Outside, where the sun does reach, await the serene landscapes and remarkable monuments of the cemetery, which is itself a National Historic Landmark .

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The Lost Sea

Image: Roberto Nickson

The largest underground lake in America is in Tennessee. Hidden within the Craighead Caverns in Sweetwater, this enormous body of water lies in a cave system filled with fascinating formations, such as stalactites, stalagmites, and rare anthodites, also known as "cave flowers."

A National Natural Landmark, this lake marvels scientists, who are yet unaware of the exact extension of its waters. Those who visit can embark on a boat ride called "The Lost Sea Adventure," first walking inside the cavern before reaching a boat to navigate these ethereal sights.

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Mammoth Cave National Park

Image: Sherin Jacob

The Mammoth Cave National Park is home to the longest cave system in the world . Located in central Kentucky, it extends over 420 miles of explored passages and many more likely undiscovered. Enormous chambers, underground rivers, a labyrinth of tunnels, and gypsum crystal formations can all be found at this site.

The park has been declared a UNESCO World Heritage Site and an International Biosphere Reserve. It also includes over 52,000 acres of protected land on the surface, renowned for its lush forests and diverse wildlife.

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Carlsbad Caverns National Park

Image: Cason Asher

A large bat colony lives in the Carlsbad Caverns National Park in New Mexico, but that’s not its only charm. The park boasts over 100 caves, with its centerpiece being the immense Carlsbad Cavern.

The cavern includes the Big Room, one of the largest underground chambers in North America, spanning 8.2 acres. Visitors can descend via an emblematic natural entrance or by elevator, dropping 750 feet underground. Stalactite formations like the Giant Dome, the Hall of the White Giant, and the Chandelier are some of the caves' breathtaking highlights.

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Indian Echo Caverns

Image: Magda Ehlers

The Indian Echo Caverns, which have been open to the public since the early 1920s, are carved into the limestone of the Appalachian Mountains. Located near Hummelstown, Pennsylvania, this site gets its name from the echoes heard within the cavern’s chambers , which were once believed to be mystical by Native American people in the area.

Unique, immersive sections of the caverns have names like the "Crystal Palace," the "Echo Room," and the "Wedding Room," where, yes, real weddings are sometimes held!

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Wind Cave National Park

Image: Francesco Ungaro

Wind Cave National Park, located in the Black Hills of South Dakota, is one of the world’s largest caves, but that’s not what it’s most famous for. One signature sight here is the boxwork formation , a rare lattice-like pattern formed by calcite deposits.

The cave system stretches for over 140 miles, though much of it remains unexplored. Popular tours take guests through captivating features like the "Ribbon Room" and the "Crystal Palace."

Why is Wind Cave called that? Mainly due to the "wind" phenomenon that occurs at its entrance. The cave's air pressure causes the entrance to draw in or expel air, depending on atmospheric conditions.

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Money Materials

Image: Jorge Salvador

We call them paper bills, but do they undergo the same process as any other paper? Naturally, they don’t. U.S. bills are mainly made of two materials: 75% of their composition is cotton and the 25% left is linen. Besides, they have randomly disbursed red and blue security fibers embedded in the paper.

This special blend is made by only one company in America and that is Crane & Co . The company, based in Massachusetts patented this special blend and it has been the sole provider of paper for currency since 1879.

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Origin of the U.S. dollar symbol

Image: Paris Bilal

The dollar sign is a matter of debate. One line or two across a capital S, the symbol is today a worldwide sign for money, but where does it come from?

Even if there are several theories as to where the U.S. dollar symbol comes from, all of them agree that it was derived from the Spanish peso . When the time came, and the new nation needed its own currency, the basis was that of the Spanish coinage, which was the most common currency in the colonies before the country’s independence.

The adoption of the sign was made official in 1785, and today, the United States is not the only country that uses this symbol, Canada, Australia, and New Zealand do too!

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Who appears on the bills?

Image: AR

Having your face forever stamped on the little piece of paper that rules the world should be a milestone in your career, right? However, there were certain rules as to who qualifies to be granted this honor .

Probably, the most surprising, yet the most logical one is that no living person can be portrayed in American currency. Since the Founding Fathers considered it unpatriotic to be portrayed while alive, this was first a tradition and then made official in an Act of Congress in 1866 .

However, contrary to popular belief, this honor is not only reserved for presidents! Anyone who contributes to the nation can be portrayed.

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Folding Papers

Image: Emilio Takas

Bills come and go all the time. We take them out of our pockets and put them in our purses only to take them out again a few hours later and give them to the shop assistant. For a life that busy, we can only hope the paper is tough enough , right?

Well, as a matter of fact, it is. Compared to regular paper, which can only be folded 400 times before it breaks, money paper can be folded up to 8,000 times before it breaks .

It's not that you’re going to try it out and see, but you can rest assured: Fold your bills away, they can handle it!

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Damaged Goods

Image: Jp Valery

Even if they can be folded that many times, the life of bills is limited, not to mention accidents happen. Who hasn’t sent a bill to the washing machine by chance?

So, what happens when a bill is damaged? Well, at least 50% of it has to be clearly identifiable for the bank to replace it , otherwise, you’ll just lose your money. You don’t feel like folding them much now, right?

On the other hand, and mainly due to time damage, at least 70% of the new bills are used to replace old bills . These bills, once taken out of circulation are shredded and sent to companies that can recycle them!

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Security Features

Image: Colin Watts

Counterfeiting has been a problem ever since paper money was created and statistics about which countries counterfeited most of the money are simply shocking. But we won’t get into that.

What we will say is that thanks to technological advancement, the U.S. bill is getting harder and harder to counterfeit. In modern bills, there are at least six security features which are: UV security ribbon, raised printing, microprinting, 3D security ribbon, color-shifting ink, and traditional watermarks. Do you pay attention to them?

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U.S. Coins

Image: Kenny Eliason

Coin production in America is in charge of the U.S. Mint and there are four production facilities across the country. They are located in Philadelphia, Denver, San Francisco, and West Point.

It is estimated that every year the Mint produces about 16 trillion coins which are valued at over $1.09 billion dollars. What is truly impressive is that Americans throw away an estimated 62 million dollars worth of coins every day!

They may not be worth much alone but don’t throw them away, all of them together can make you rich!

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Green Ink

Image: maria pagan

Have you ever wondered why the U.S. dollar bills were green? It is not about design or aesthetics, even if we think they look pretty.

The decision to use green ink was a matter of security, in order to prevent counterfeiting. Back then, black and white ink made it easier to create photographic fakes. For that reason, green was the color of choice, and, when paper money was standardized in 1929, it had great acceptance due to the positive connotations of the color . Do you like it?

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Andrew Jackson’s Take on Paper Money

Image: Elsa Olofsson

Every denomination has an important figure stamped on the front. In the case of the 20-dollar bill, Andrew Jackson was the chosen one.

Jackson was the seventh president of the United States and, even if it is not a rule that only presidents can be portrayed, his contributions gained him this honor.

Ironically, Jackson was not in favor of using paper money. For him, only gold and silver coins should have remained legal tender. After learning this, one can only assume he wouldn’t be so happy to be the face of the 20-dollar bill, right?

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Facelifts and redesigns

Image: Kenny Eliason

One of the ways of keeping paper money safe and hard to counterfeit is by giving the bills new designs.

New faces were expected to appear in future bills, but, in the meantime, the changes always had to do with the proportions of the elements within each denomination. Bigger faces, rearrangement of the signatures, stuff like that.

Now, these changes and facelifts haven’t reached all the bills. 1-dollar bills haven’t been changed or redesigned ever since 1929. Why is that? Because it is not worth the trouble for criminals to counterfeit. One dollar won’t take them too far!

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The original plan included full-body figures

Image: Thomas Shockey

Mount Rushmore was supposed to be even more colossal than it already is. Sculptor Gutzon Borglum envisioned the four presidents carved from the waist up .

He even made plaster models showing Abraham Lincoln's coat folds and Teddy Roosevelt’s hand clutching his lapel. But as costs went up, Congress said: "heads only, please."

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Charles Rushmore was just a curious New Yorker

Image: Maarten van den Heuvel

Back in 1925, when the mount was about to be carved into a monument, Charles Rushmore wrote a letter explaining why the peak bore his name. He recalled that in the 1880s he was a young New Yorker working in the area, and fell fond of that particular granite peak .

When he asked the locals about it, they informed him that it had no name, but that if he wished so, they would just start calling it Rushmore Peak, or Mount Rushmore, or the likes. Years later, that very name had been inscribed in the public domain to designate the peak.

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Yes, there’s a hidden room behind Lincoln’s head

Image: Laura Nyhuis

Behind Abraham Lincoln’s hairline lies a hidden chamber, part of Borglum’s lofty idea for a "Hall of Records." This room was meant to house foundational American documents like the Constitution or the Declaration of Independence.

Instead of that, in 1998, a titanium box was placed inside, filled with copies of important documents and biographies, as a time capsule to preserve the treasure of knowledge for future generations.

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Thomas Jefferson was moved

Image: Dave Baraloto

Jefferson was originally supposed to go to Washington’s right, but after 18 months of chiseling , the granite betrayed them. Cracks and flaws made the site unworkable.

Borglum made the painful decision to blast Jefferson’s half-formed face clean off and start anew on Washington’s left.

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The mountain was almost a monument to western heroes

Image: Timberly Hawkins

Before presidents took over, the mountain was pitched as a giant tribute to the Wild West . South Dakota historian Doane Robinson wanted to see frontier legends like Lewis & Clark carved into the Black Hills.

But when Borglum came aboard, he had a grander (and more politically bankable) idea: four presidents to symbolize national unity and expansion.

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A woman’s face was almost added

Image: Tom Fournier

In the 1930s, there was serious talk of honoring Susan B. Anthony alongside the Founding Fathers, as a nod to the women’s suffrage movement.

Borglum wasn’t opposed to the idea, but Congress quickly nixed it, stating that only U.S. presidents could be included.

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The workers were mostly local miners and loggers

Image: Pixabay

They were neither sculptors nor artists. Most of the workforce came from nearby Keystone, South Dakota: miners, loggers, and hard-up laborers looking for work during the Great Depression.

Borglum trained them himself. There were no safety harnesses, and yet, remarkably, no one died on the job.

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Dynamite did 90% of the work

Image: Alexander Paramonov

To carve the faces of Washington, Jefferson, Roosevelt, and Lincoln, workers used carefully timed dynamite blasts to remove over 450,000 tons of rock. They got so precise, they could blast within inches of where the final surface would be.

The last details, like wrinkles, pupils, or Roosevelt’s glasses, were done with jackhammers and chisels.

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The noses are disproportionate

Image: Dudubangbang Travel

Standing in front of the mountain, the faces seem alright. But that’s a trick of perspective. Each presidential nose is a whopping 20 feet long .

If the sculptures had included full bodies as planned, each figure would have stood 465 feet tall. That’s taller than the Statue of Liberty and most downtown skyscrapers.

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Teddy Roosevelt was the most controversial pick

Image: Dudubangbang Travel

Washington, of course. Jefferson, made sense. Lincoln, sure. And Teddy? Some critics raised their eyebrows at Borglum’s fourth choice. Roosevelt had only recently passed away in 1919, and many questioned whether he'd stood the test of time.

But Borglum defended the decision Roosevelt’s role in breaking up monopolies, conserving national parks, and engineering the Panama Canal. Plus, Borglum had met him personally and was a fan.

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It was supposed to have inscriptions

Image: Dan Pick

Borglum had grander plans than just four giant heads. He wanted to carve a massive inscription next to them, a timeline of America’s most important milestones , chiseled straight into the mountain. In time, the idea was scrapped for practical and aesthetic reasons.

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The visionary died before completion

Image: Lisa Reichenstein

Gutzon Borglum, the visionary behind it all, didn’t live to see his masterpiece finished. He died in March 1941, just as the construction was reaching its end. His son, Lincoln Borglum (yes, named after that Lincoln), took over the project.

Still, with WWII drawing resources elsewhere, funding was slashed, and Lincoln had to wrap things up quickly . Some features, like Lincoln’s ear, were never fully detailed.