1

Seattle: The Seattle Underground

People usually visit Seattle for the seafood, waterfront views, coffee culture, and the famous Space Needle. But underneath the busy sidewalks lies part of the city most tourists never realize exists. Beneath Pioneer Square sits the Seattle Underground, a network of old streets and storefronts buried below modern Seattle.

This area dates back to the Great Seattle Fire of 1889, which destroyed much of downtown. City leaders decided to rebuild the streets one story higher to improve drainage problems that had plagued the city for years. For a while, businesses operated below street level, but eventually this lower level was abandoned. Today, guided tours take visitors through the underground passageways and old sidewalks and mix ghost stories and old city legends with the real story below Emerald City.

2

Chicago: The Chicago River

Between deep-dish pizza, Wrigley Field, jazz clubs, and the towering skyscrapers, few cities feel more American than Chicago. It’s also home to the magical Chicago River, which, in 1900, actually flowed backwards.

Back in the late 1800s, Chicago faced a dangerous problem. The river carried sewage and industrial waste into Lake Michigan, the same lake supplying the city’s drinking water. Disease outbreaks of typhoid and cholera became increasingly serious, and engineers realized something drastic had to happen. In 1900, after years of planning and digging canals, they built a series of canals and locks, like the prominent Chicago Sanitary and Ship Canal, connecting the Chicago River to the Des Plaines River, forcing the water to flow toward the Mississippi River watershed. That way, they reversed the river’s direction so the contaminated water would flow away from the lake instead of into it. The natural flow was forever altered, but it remains central to city life, especially during St. Patrick’s Day when, according to tradition, it’s dyed bright green every year.

3

New York City: NYPL hidden apartment

Yellow taxies, Central Park, Broadway shows, and nonstop energy have made New York City feel magical. The Big Apple hides many secrets, and the apartment inside the New York Public Library Main Branch is just one of them.

In 1910, the library superintendent, John Fedeler, and his family moved into a private eight-room apartment tucked inside the library. This was so that someone would always be available to maintain the huge building. With bedrooms, a kitchen, and a living area, a full home is hidden behind doors that most visitors passed by. The family lived there until 1941, when the space was converted into offices and storage areas. However, the library still offers tours where visitors can learn about its history.

4

Portland: Mill Ends Park

When you think of Portland, you may think of Washington Park or Forest Park. But if you pay close attention, you can also visit Mill Ends Park. At just two feet across, it holds the Guinness World Record as the world’s smallest park.

At first glance, it looks more like a flowerpot than a public landmark, but the story goes back to 1948, when journalist Dick Fagan noticed an empty hole that had been meant for a light pole. Tired of staring at it from his office window, he planted flowers there and jokingly claimed that, since it was so small, it was a park for leprechauns. The joke took on a life of its own, and in 1976, it was dedicated on St. Patrick's Day. Today, it’s a must-do for travelers going through Portland, and locals continue treating it with surprising seriousness.

5

Houston: The Beer Can House

Everything is bigger in Texas, and Houston is no exception. If you’ve been there, you’ve probably visited NASA, the Museum District, and tried a local barbecue joint. But you’ve probably missed a quirky house hidden among the neighborhoods. Located at 222 Malone St, sits the Beer Can House. The name is self-explanatory, since it’s a house covered with beer cans.

In 1968, John Milkovish decided he was tired of painting and maintaining the exterior of his property. Instead, he began flattening beer cans and attaching them to the house. What started as a hobby slowly turned into a full-blown obsession involving more than 50,000 cans. The house went from being a neighborhood curiosity to a roadside attraction to finally being a protected local landmark in 2001. In 2010, Time magazine even ranked it as one of America's top 50 roadside attractions. True to his Texan blood, John Milkovish built something big.

6

San Francisco: The Wave Organ

No trip to San Francisco is complete without taking the cable car or a picture at the Golden Gate. But tucked away near the Marina District is an attraction many tourists completely miss. The Wave Organ is a gigantic acoustic sculpture that turns ocean waves into music.

Completed in 1986 by artist Peter Richards, t he installation consists of a series of pipes extending into the bay. As tides rise and waves move through the pipes, they create eerie sounds ranging from soft bubbling to deep echoes. Richards was inspired by recordings of artist Bill Fontana, made of sounds coming from a vent pipe of a floating concrete dock in Sydney, Australia. In 1980, he received a grant from the National Endowment for the Arts and tested the first prototypes during the 1981 New Music Festival. Five years later, he completed this sonic sculpture that runs entirely on nature.

7

Los Angeles: La Brea Tar Pits

Los Angeles is all about Hollywood, palm trees, and the beaches. But it’s also home to one of the world’s most important prehistoric sites. The bubbling black pools at La Brea Tar Pits have been trapping animals for tens of thousands of years.

Long before Los Angeles was the city it is today, natural asphalt constantly came up from underground. Mammoths, saber-toothed cats, dire wolves, and other Ice Age animals became trapped there, preserving their skeletons remarkably well. Scientists began excavating fossils in the early 1900s, and discoveries continue to this day. The fossils recovered from the site are countless. Visitors can explore the museum for $18 and watch active excavations while surrounded by modern office buildings and traffic.

8

Seattle: The Giant Shoe Museum

Seattle already has its share of unusual attractions, especially around Pike Place Market, where fishmongers toss salmon through the air, and crowds line up for fresh pastries. But the Giant Shoe Museum, located there, is even stranger. A single exhibit wall dedicated to oversized footwear , the museum works like an arcade peep show. Visitors drop coins into viewing slots to reveal displays featuring enormous boots, giant clown shoes, and other gigantic footwear.

The museum was founded in 1997 by Danny Eskenazi after he became obsessed with his grandfather’s missing item: the shoe of Robert Wadlow, the tallest man in history. He even offered $1,000 to anyone who could find that Wadlow shoe. Sadly, the shoe remains lost, but his obsession led to the discovery of other shoes worn by Wadlow and more footwear that is now displayed in the museum.

9

Boston: Great Molasses Flood Site

Boston's most popular spots blend colonial and Revolutionary War history with vibrant neighborhoods that feature top attractions like the Freedom Trail, Fenway Park, and the Boston Public Garden. But it’s also home to the remains of a disaster.

In 1919, Boston experienced the Great Molasses Flood. A massive molasses storage tank burst in the North End neighborhood, unleashing more than two million gallons of syrup into the streets. After 21 people lost their lives, the disaster led to stricter construction safety regulations across the country, and the tank was never rebuilt. Today, visitors can still walk through the neighborhood where it happened. There’s no giant syrup wave anymore, thankfully, but plaques and local tours continue telling the story.

10

Lake Havasu City: The London Bridge

Driving through Lake Havasu City in Arizona, you expect desert landscapes, boating, and blazing summer heat. You probably don’t expect to stumble across a famous bridge from England, especially not the original London Bridge itself.

In 1831, John Rennie designed and opened the London Bridge spanning the River Thames. By the 1960s, the bridge started sinking under the weight of modern cars and traffic. Robert P. McCulloch, founder of Lake Havasu City, saw this as an opportunity and, in 1968, he purchased the bridge for $2.4 million. The bridge was dismantled and reconstructed in the Arizona desert, and completed in 1971. What once connected two sides of London now links mainland Lake Havasu City with Pittsburgh Point that visitors and locals enjoy every day.

11

Atlanta: The Center for Puppetry Arts

Atlanta is often associated with Southern cooking, a busy airport, and its important role in the Civil Rights Movement. But tucked inside the city is also the Center for Puppetry Arts, which houses the world’s largest collection of Jim Henson’s original Muppets.

The center opened in 1978, when puppeteer Vincent Anthony transformed a former elementary school into a home for puppet arts. From the very beginning, the project had a special connection to Jim Henson himself. He and Kermit the Frog helped inaugurate the center, and over the years, Henson became one of its biggest supporters. The center expanded significantly between 2007 and 2015, adding the permanent Jim Henson Collection and the impressive Worlds of Puppetry Museum. Unlike many museums, this place is hands-on. Guests can watch live performances, explore exhibits from puppet traditions, and revisit characters that shaped generations of childhood memories.

1

What are bills made of?

Unlike other currencies, dollar bills are not made of paper or plastic. U.S. dollar bills are made from a special fabric blend composed of 75% cotton and 25% linen. This mix makes the bills extremely durable and resistant, and they can be folded about 4000 times before tearing.

2

What bills are valid?

Any U.S. dollar bill that was legally printed is valid, no matter how old, as American currency does not have an expiration date. While some bills might not be accepted by businesses of foreign exchange services due to their condition or if they are a discontinued version of the bill, the bills themselves are still valid, and American banks will accept them, though they might take them out of circulation.

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American leaders

Five bills have a depiction of an American president. The exceptions are the $10 bill, with Alexander Hamilton on the front, and the $100 bill, with Benjamin Franklin. The $1 bill, depicting George Washington, is extremely symbolic: several elements are repeated 13 times as a nod to the thirteen colonies, and it showcases the Bald Eagle and the Eye of Providence as a sign of God watching over America.

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A change in size

Did you know that dollar bills used to be so big that they were nicknamed "horse blankets"? Original dollar bills were 7.4 × 3.1 inches. In 1929, the Treasury Department reduced the size of bills to 6.14 × 2.61 inches to reduce production costs and materials. Old bills, though still valid, are worth much more as collector items.

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Uniformity

Besides their value and design, all dollar bills have the same size (6.14 × 2.61 inches), color, and weight (1 gram) , which sets American currency apart from other countries where bills of different values are differentiated by size, color, or both. Why doesn’t the U.S. implement differences among bills? The cost of adapting vending machines, bank drawers, and ATMs to new bill sizes would cost billions of dollars.

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Hard to copy

Originally, dollars were not green, but black. As time passed, green ink was favored, as it was cheap and did not fade as much as black. The new color also prevented people from using black-and-white cameras to create counterfeit money. Currently, dollar bills are predominantly green, but newer versions also include extra colors, such as pink, orange, or purple.

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A $100,000 bill?

Have you ever seen a $500 or 1,000 dollar bill? What about a $100,000? Up until 1945, the U.S. Treasury printed $500, $1,000, $5,000, $10,000, and $100,000 notes , in addition to the values currently in use. These higher-value notes were mainly intended for bank and government use, but were sought by criminals as they made it easier to hide large amounts of money. Even though they were officially discontinued in 1969, these notes are still valid, though rare, and they have a high worth as collector's items.

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No numbers

Unlike bills, American coins have different sizes and colors related to their value. Originally, gold, silver, and copper were used for coins, but modern coins are made of copper, zinc, or nickel. Besides their size and design, the value of each coin is printed in letters, not in numbers , alongside depictions of American presidents.

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Liberty for all (the coins)

By law, all American coins must include six specific details : the word ‘Liberty’, the name of our country, the national motto "In God We Trust", the oldest American motto "E Pluribus Unum", the value of the coin, and the year. Each coin also includes a mint mark that shows where it was made: "P" for Philadelphia, "D" for Denver, "S" for San Francisco, and "W" for West Point.

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A global currency

The American dollar is one of the most powerful currencies in the world, acting as a backbone for international trade and finances. It is estimated that two-thirds of the physical dollars in circulation are outside American territory. Besides the U.S. and its territories, eight sovereign nations have the U.S. dollar as their official currency, with several more accepting it as legal tender.

1

There's an unexplained billion-year gap

Look closely at the canyon walls, and you'll notice something strange: a clean, sharp line where ancient rock simply stops, and a much younger layer begins directly above it.

This geological puzzle is called the "Great Unconformity," and it represents over a billion years of rock layers that are simply absent , as though that stretch of time never happened. In some spots, rock dated 1.8 billion years old sits directly beneath rock that is only 520 million years old. Where did the missing billion years go?

The leading theory involves the violent breakup of an ancient supercontinent, but scientists are still piecing it together.

2

During the Cold War, it hid a nuclear fallout shelter

During the Cuban Missile Crisis in 1962, the U.S. government converted part of the Grand Canyon Caverns into a fallout shelter. This dry cave system, more than 200 feet underground, was stocked with enough food and water to sustain 2,000 people. Naturally, it was never occupied, and the supplies were never used.

The caverns have since been transformed into a tourist attraction, with organized tours winding through the same underground chambers that were once intended as a refuge from nuclear war. You can even book a night's stay there.

3

The Federal Aviation Administration was founded after a crash over the canyon

In 1956, two commercial passenger planes collided in midair over the eastern Grand Canyon, killing all 128 people on board both crafts. Rescue teams struggled to reach the wreckage deep inside the canyon, and the extreme heat of the crash had caused the planes' aluminum to fuse with the bedrock. There were no survivors.

The disaster exposed a terrifying truth: the U.S. air traffic control system was dangerously outdated, relying on pilots' visual estimates and rough guesswork from controllers , with no way to separate fast-moving aircraft from slow ones, or instrument-flying planes from those navigating by sight. Congress responded by passing legislation that created both the Federal Aviation Administration (FAA) and the National Transportation Safety Board.

4

A hoax suggested that an Egyptian civilization had lived there

In 1909, the Arizona Gazette reported that an explorer named G. E. Kinkaid had discovered a vast underground citadel inside the canyon, filled with artifacts linked to ancient Egyptian civilization. He even claimed the expedition had been funded by the Smithsonian.

This story described hieroglyphics on the walls, mummies in the chambers, and relics pointing to a direct connection with the Egypt of the pharaohs. It was incredibly detailed, and it was, of course, a hoax. No evidence for any of Kinkaid's claims ever surfaced.

5

Fewer than 100 people have ever hiked its full length

Among the few people who have completed the through-hike of the Grand Canyon is Jen Hogan, the first woman to accomplish it, finishing her journey in 2021–2022.

It’s a full 800-mile length below the rim. The route involves extreme heat, flash floods, near-impassable areas, and stretches with no water or trail whatsoever. Around 60 or 70 people have reportedly accomplished it. This makes it one of the most exclusive feats on Earth.

6

The Grand Canyon's rocks predate dinosaurs entirely

Visitors scanning the canyon walls for fossils are often surprised to learn they won't find any dinosaur bones here. The rock layers of the Grand Canyon are simply older than dinosaurs. This fact alone can be shocking: staring at its walls means staring at marine fossils from as far back as 1.2 billion years ago. Some of its caves hold the remains of ancient mammals. The canyon is a window into a world that existed long before the dinosaurs, when the land that is now Arizona lay beneath a shallow sea.

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The park is bigger than Rhode Island

Numbers alone rarely capture the Grand Canyon's scale, so here's a different approach. Rhode Island covers about 1,214 square miles, and the Grand Canyon National Park spans 1,904 square miles.

The canyon's depth exceeds four Empire State Buildings (which is 1,454 feet) stacked on top of one another. That’s 6,093 feet at its deepest point.

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But it's not the deepest canyon on Earth

For all its grandeur, the Grand Canyon does not hold the depth record. Pictured above, the Yarlung Tsangpo Grand Canyon in Tibet, China, plunges to 17,567 feet, which is nearly three times deeper. Carved by the Yarlung Tsangpo River as it cuts through the eastern Himalayas, that canyon is so remote and extreme that it remained largely uncharted until the late 20th century.

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It is home to a pink rattlesnake found nowhere else on Earth

The Grand Canyon Pink Rattlesnake has a pinkish-red coloring that matches the canyon's own distinctive rock walls so closely that it's nearly invisible. It is found nowhere else in the world. Officially classified as Crotalus oreganus abyssus , it has darker diamond-shaped markings along its back that deepen the camouflage further.

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There's a village at the bottom: Supai Village

For over 1,000 years, the remote village of Supai has been home to the Havasupai Tribe, the People of the Blue-Green Waters. It is located an eight-mile hike from the rim, but sits roughly 3,000 feet deep inside the Grand Canyon.

The U.S. Department of Agriculture has called it the most remote community in the contiguous United States, and it has no automobiles and no road access. The only ways in are on foot, by mule, or by helicopter. It is also the only place in the United States where the postal service still delivers mail by mule train.