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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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Pecan pie: the South’s nutty masterpiece

Image: Keighla Exum

This rich, sticky dessert has deep Southern roots. French settlers in New Orleans encountered Native Americans who introduced them to pecans, and that’s when the magic began. Texas cookbooks helped spread the word, and Karo syrup sealed the deal in the 1930s with its bottle-side recipes. Today, pecan pie is a holiday must-have.

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The California roll’s West Coast switch-up

Image: Ben Lei

Sushi purists may scoff, but the California roll is what got a lot of Americans eating sushi. Well, kind of. Created in Los Angeles (though Vancouver, Canada, also claims the credit), this roll swapped raw tuna for avocado and imitation crab, making sushi less scary and way more approachable.

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Fajitas, from cattle hands to cast iron

Image: Nadine Primeau

Back in the day, ranch workers along the Texas-Mexico border made the most of tough skirt steak by grilling it and tossing it into tortillas. That no-frills meal eventually became the sizzling skillet spectacle we now call fajitas. Toss in onions, peppers, and a dollop of guac, and boom! Tex-Mex gold.

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Corn dogs and the mystery on a stick

Image: Taylor

A hot dog on a stick sounds simple—we know—but getting to the modern corn dog took some trial and error. Patents were filed, batter recipes tweaked, and somewhere between a beach shack in Illinois and a fairground in Texas or Oregon, the corn dog was born. One thing’s for sure: once Americans figured out how to deep-fry a hot dog in cornmeal, there was no going back!

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S’mores and the sweet tooth showdown

Image: Jonathan Taylor

Did you know the Girl Scouts have such a legacy? Their 1927 handbook gave us the first printed recipe for s’mores, and we’ve been hooked ever since. Roast a marshmallow, squish it between graham crackers and chocolate, and try not to eat five. Campfire memories wouldn’t be the same without this gooey, finger-sticky treat. And yes, of course—they stand for "some more."

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The Caesar salad’s border-crossing fame

Image: Frames For Your Heart

Italian chef Caesar Cardini whipped up this leafy dish not in Rome, but in Tijuana. During the Prohibition era, Americans sneaked over the border for a legal drink and left raving about the crunchy, garlicky salad. It may have Mexican birth papers, but with Hollywood stars singing its praises and the dressing later patented in the US, the Caesar salad became a true celebrity.

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Philly cheesesteaks: city of hoagie love

Image: Syed F Hashemi

Philadelphia's most famous sandwich started with a hot dog stand and a hunk of beef! Pat Olivieri slapped some steak on a roll, later added cheese, and boom—the cheesesteak was born, and the rest is history. Locals still argue over where to get the best one, but everyone agrees it’s a sandwich worth standing in line for.

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Spaghetti and meatballs, made the American way

Image: Ivy Farm

If you order spaghetti and meatballs in Italy, they’ll look at you funny. Why? Because this comfort food classic was created by Italian immigrants in New York. Meat was cheaper here, sauce was plentiful, and suddenly, Sunday dinner had a new star. It’s Italian by ancestry but all-American in execution.

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Chocolate chip cookies, thanks to a happy accident

Image: SJ 📸

Sometimes the best things happen by mistake. Here’s an example: Ruth Wakefield, owner of the Toll House Inn, wanted to make chocolate cookies but didn’t melt the chocolate—and voilà, the chocolate chip cookie was born. Nestlé acquired the recipe, and now it’s printed on every bag of chips. Homemade, store-bought, or eaten straight from the dough, this cookie is as American as it gets.

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Jambalaya and its melting pot roots

Image: Kalyani Akella

Let’s close things out with a burst of flavor: Jambalaya may have a European passport, but it earned its American green card in Louisiana. Spanish paella, West African jollof rice, and French seasonings all came together in New Orleans, where rice, meat, and veggies came together to create one exquisite dish for everyone to enjoy!

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Keep Austin weird (Austin, Texas)

Image: MJ Tangonan

We’ll begin with one of the most distinctive unofficial mottos out there. In the year 2000, an Austin resident named Red Wassenich called a radio show and made a pledge encouraging fellow citizens to " Keep Austin Weird ." The phrase resonated with him, and he soon began printing bumper stickers and shirts. It was quickly embraced by other Austinites, eventually evolving into the unofficial motto still seen all over the Texas capital.

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Al-Ki (Washington)

Image: Toan Chu

The only American state that has a fully unofficial state motto. " Al-Ki " (also written as "Alki") is a word from Chinook Jargon that translates to "by and by," though it’s sometimes interpreted as " hope for the future ." Whichever translation you prefer, both express a beautiful sentiment—one that reflects not only the optimism of early 19th-century settlers but also the warm, forward-looking spirit of the people of Washington State.

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Land of Lincoln (Illinois)

Image: Joel Mott

Illinois takes great pride in being the home state of our 16th president—and with good reason. Who wouldn’t be proud of " The Great Emancipator "? Interestingly, Lincoln wasn’t born in Illinois; he was born in a log cabin in Kentucky and spent much of his childhood in Indiana. However, Illinois was definitely Lincoln’s home : it was in the "Prairie State" that he made a name for himself as a lawyer and met his future wife.

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Sportsman’s Paradise (Louisiana)

Image: Fitsum Admasu

If you’ve ever visited the great state of Louisiana, you’ve probably noticed the many outdoor opportunities it offers, including abundant hunting, fishing, and trapping spots. While Louisiana’s official motto is "Union, Justice, and Confidence," many know the Pelican State by another moniker: "Sportsman’s Paradise."

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Smiling faces, beautiful places (South Carolina)

Image: Jacqueline Munguía

One of the most memorable aspects of visiting the American South is experiencing its famous " Southern hospitality ." People from the South take pride in their warmth, kindness, and the instinctive way they welcome visitors. In that spirit, South Carolina’s unofficial motto perfectly reflects these values . After all, if you ever visit this great state, be prepared to be greeted by the two things it’s best known for: "Smiling Faces, Beautiful Places."

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Taxation without representation (Washington, D.C.)

Image: Louis Velazquez

Most license plate mottos praise the state or city they represent. However, since 2000, Washington, D.C. has famously used a slogan that protests its unique political situation. For over 20 years, D.C. license plates have featured a variation of the phrase "Taxation Without Representation"—a quote that highlights the fact that D.C. residents must pay federal taxes without having voting representation in Congress.

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Wild, wonderful (West Virginia)

Image: Sharosh Rajasekher

There’s nothing like a good alliteration to lift your spirits. West Virginia is known worldwide for its beauty—a living reminder that good things come in small packages . What the state lacks in size, it makes up for with its stunning scenery. In that spirit, we’d like to celebrate whoever coined West Virginia’s most famous unofficial motto: "Wild, Wonderful." It’s short, simple, and perfectly captures the essence of this remarkable state.

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America’s Dairyland (Wisconsin)

Image: Brian Suman

Wisconsin is known around the world for the exceptional quality of its dairy products, and Wisconsinites take great pride in that fact. Don’t believe it? Just look at the fans of the Green Bay Packers, who often wear iconic "cheesehead" hats shaped like wedges of cheese, proudly celebrating their state’s most famous export. While the official state motto is the single word "Forward," many prefer Wisconsin’s unofficial title: "America’s Dairyland," a nickname that appears frequently across the state.

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Life Elevated (Utah)

Image: Taylor Brandon

In 2006, Utah’s Department of Tourism introduced a new slogan to promote tourism and inspire residents to take pride in their beautiful state. The slogan, "Life Elevated," was featured on tourism signs and license plates throughout "The Beehive State." When you think about it, the slogan is quite clever, especially considering it indirectly references one of Utah’s most beloved natural wonders: Arches National Park.

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Old Dominion (Virginia)

Image: STEPHEN POORE

From "the Mother of Presidents" to "the Mother of States," Virginia boasts a collection of iconic nicknames . While "Old Dominion" may not be as self-explanatory as some other monikers, it’s no less impressive. The name originates from Virginia being the first overseas dominion of the English kings and queens .