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The disaster exposed a terrifying truth: the U.S. air traffic control system was dangerously outdated, relying on pilots' visual estimates and rough guesswork from controllers , with no way to separate fast-moving aircraft from slow ones, or instrument-flying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

Less 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.

7

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.

8

But it's not the deepest canyon on Earth

For all its grandeur, the Grand Canyon does not hold the depth record. Pictured above, 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.

9

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.

10

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 eight miles below the rim of 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.

1

Blockbuster

During the 1980s and 1990s, Friday night often meant one thing for American families: a trip to Blockbuster. Browsing the aisles for a movie, debating what to watch, and grabbing popcorn at the counter became a weekly routine. But nothing lasts forever.

Born in 1985, Blockbuster conquered the massive home-video market with thousands of stores by the late 1990s and early 2000s, catering to families with at-home VCRs. Then technology changed everything. First came DVD-by-mail services like Netflix, followed by streaming, which left Blockbuster struggling. Late fees and inconvenience only pushed more customers away. The company filed for bankruptcy in 2010. Today, just one official store remains in Bend, Oregon, where visitors still stop by for a dose of the video-store era.

2

Kodak

Back in the day, almost every vacation, birthday, wedding, or holiday gathering seemed to include a Kodak camera, or at least a roll of Kodak film. Founded in 1881, Kodak helped keep the moments that filled family photo albums for generations.

From the 1960s through the 1990s, Kodak dominated the world of film and photography. But that success also made the company slow to accept that technology was changing. Ironically, Kodak helped invent one of the first digital cameras in 1975, yet it hesitated to embrace the future. By the 1990s and 2000s, digital cameras (and later camera phones) quickly replaced traditional film. In 2012, the company declared bankruptcy.

3

Pan Am

Long before flying became an everyday experience, Pan American World Airways, better known as Pan Am, was already carrying Americans across the world. It was founded in 1927, and during the 1960s and 1970s, the airline became a symbol of glamorous air travel.

Its famous blue globe logo was instantly recognizable, even to those who rarely flew. But by the late 1970s, rising competition, fuel costs, and financial troubles began weakening the company. After years of mounting losses and debt, Pan Am shut down in 1991. Even so, its fame was such that even today, more than 30 years later, we still remember it.

4

Woolworth’s

Before Woolworth's made the "five-and-dime" famous, shopping in America looked very different. For decades, Americans visited Woolworth’s for everything from toys and school supplies to household goods and everyday essentials. By the 1960s, the brand had become a familiar part of American life.

Created in 1879 by Frank Winfield Woolworth, the chain grew into one of the country’s largest retailers. But in the 1970s, malls and discount giants like Walmart changed the way Americans shopped, and Woolworth struggled to keep up. By the 1980s, the iconic chain was slowly disappearing. Most stores closed during the 1990s, and the Woolworth retail chain officially ended in 1997.

5

Circuit City

Testing giant stereo systems, browsing rows of CDs and video games, and shopping for the newest TV were all part of the experience at Circuit City, once one of America’s biggest electronics chains.

Founded in 1949 by Samuel S. Wurtzel in Richmond, Virginia, as "Wards Company," the retailer adopted the Circuit City name in 1984. During the 1980s, 1990s, and early 2000s, it became the go-to place for Americans buying a TV, stereo, computer, or any electronic device. But like many companies on this list, Circuit City struggled as shopping habits changed and online stores became more convenient. A controversial 2007 decision to lay off thousands of experienced employees further hurt the company’s reputation. Circuit City couldn’t survive mounting losses and closed all remaining stores in 2009.

6

Borders

Remember Borders? Born in 1971, its huge stores, filled with books, music, magazines, and cozy reading spaces, invited customers to spend entire afternoons there.

During the 1990s and early 2000s, the rise of large shopping malls actually helped Borders thrive, turning its bookstores into popular destinations inside malls across the US. But eventually, the company ran into a challenge it couldn’t overcome: online shopping and digital reading. Competitors like Amazon surged ahead, while Borders struggled to adapt and made costly business decisions, including outsourcing its online sales to Amazon for years. The company collapsed financially in 2011 and soon closed all remaining stores.

7

Bugle Boy

In the late 1980s and early 1990s, teenage fashion became almost synonymous with Bugle Boy. Famous across the country for its casual jeans and memorable TV commercials, the brand became a major part of American mall culture and was sold in department stores nationwide.

But fashion never stands still, and brands have to constantly adapt to survive. By the late 1990s, newer youth-oriented labels had taken over with fresh styles that quickly made Bugle Boy seem outdated. Sales began to fall, and after years of struggling to keep up with changing trends, the company closed its stores in 2001.

8

Howard Johnson’s restaurants

During the 1960s and 1970s, a stop at Howard Johnson's was part of the classic American road-trip experience for many families, and that was no accident.

Founded in 1925 in Quincy, Massachusetts, the famous orange-roofed chain reached its peak when America’s expanding highways and booming car culture made roadside travel more popular than ever. But by the late 1970s and early 1980s, the growing popularity of fast-food chains like McDonald's began changing the way Americans ate on the road. Drivers increasingly wanted meals that were faster, cheaper, and more standardized, while interstate highways also redirected traffic away from many older roadside locations. Unlike some other brands on this list, Howard Johnson’s faded away slowly over the decades. The last restaurant finally closed in 2022.

9

Burger Chef

In 1958, a name emerged as one of the pioneers of America’s growing fast-food industry: Burger Chef. By the late 1960s, the chain had more than 1,000 locations across the country and had become one of McDonald's’s biggest competitors.

Long before Happy Meals became famous, Burger Chef helped popularize the idea of marketing meals directly to children with toys and themed publicity. But during the fast-food wars of the 1970s, competition became fiercer than ever. While McDonald’s and Burger King expanded by leaps and bounds, Burger Chef struggled with financial problems and changing consumer tastes. In 1982, the company was sold to Hardee's, which gradually converted most Burger Chef locations into Hardee’s restaurants.

10

Sports Authority

Throughout the 1990s and 2000s, many Americans looking for running shoes, gym shorts, and sports gear headed straight to Sports Authority.

Known for its huge stores packed with athletic apparel, exercise equipment, bicycles, camping gear, and team sports products, Sports Authority became the ideal shopping destination for families and athletes across the US. But as online shopping rapidly changed retail in the 2000s, the company struggled to adapt. Heavy debt from expansion efforts and a slow shift to e-commerce eventually caught up with the chain. Sports Authority declared bankruptcy in 2016 and closed all remaining stores later that year.

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.

3

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.

4

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.

5

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.

6

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.

7

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.

8

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.

9

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.

10

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.