1

Raven Rock Mountain Complex

Image: Ilagam

Did you know that in the 1950s, the US government carved out a secret underground city that could survive a nuclear attack? It’s called an "underground Pentagon", and very much like Area 51, it is one of the government's most classified projects.

This military complex and nuclear bunker is located near Blue Ridge Summit, Pennsylvania, 768 feet below the ground. It’s protected by 23.5 ft thick 30-ton doors built on top of springs to survive the shock from a blast. Raven Rock has five buildings with 15 floors big enough to live and work. The base has everything it needs to keep running, like a cafeteria, a barbershop, water generators, and even a medical center.

2

SubTropolis

Image: mwewering

Below Kansas City, Missouri, lies the world's largest underground business complex. SubTropolis is a structure located inside a mine north of the Missouri River. It was carved out of limestone some 135 to 185 feet underground and covers a total of 55 million square feet.

Kansas City Chiefs founder Lamar Hunt built this subterranean city in the 1960s. It has offices, storage space, and even factories. Over 1,600 people work here every day, largely because SubTropolis remains cool all year, making it an ideal location for businesses. Fun fact: some of Hollywood’s most beloved masterpieces are kept here, including the original film reels of Gone with the Wind and The Wizard of Oz.

3

Underground Atlanta

Image: Ronny Sison

Underground Atlanta is a historic spot in downtown Atlanta, Georgia. It was built in the late 1800s, right after the Civil War, as a commercial district centered around the railroad. In the 1920s, viaducts were built and the streets were raised, creating a second level of streets, buildings, and shops.

During Prohibition, the abandoned underground space served as the best spot for speakeasies and juke joints. For decades, people forgot about the hidden city, but in the 1960s, it was brought back to life as a fun place for music bars and nightlife.

4

New York City Subterranean World

Image: Photographer: unknown, Public domain, via Wikimedia Commons

Under America’s most populous city, there's a whole hidden world. For example, beneath Little Italy and the Public Library, there are secret vaults. Beyond the subway millions of people use daily, there is City Hall station, opened in 1904 and closed in 1945. It's a hidden gem with stained glass and mosaics that you can still visit by staying on the 6 train past the last stop.

But that’s not all! There are trading tunnels in SoHo and old cattle tunnels in the Meatpacking District. Also, in 1897, there were mail tubes built around the city to send letters between post offices that operated until the 1950s. Some of these underground spaces go as deep as 800 feet!

5

Permafrost Tunnel Research Facility

Image: Paxson Woelber

A large part of the land in the northern hemisphere is Permafrost, so it makes sense that there is a research facility specially built to study it. The Permafrost Tunnel in Alaska is the best place to learn about frozen soil that's over 40,000 years old.

The long tunnel was dug from 1963 to 1969 to study how to build and mine in frozen environments. Inside the facility, scientists study ice, ancient plants, and even bones from animals like mammoths. The tunnel shows different layers of earth, uncovering frozen ground from different time periods that help scientists anticipate what might happen as the world gets warmer.

6

The Greenbrier Bunker

Image: Alex Holzreiter

The Greenbrier Bunker in White Sulphur Springs, West Virginia, is a secret underground facility beneath a luxury hotel that has hosted numerous US presidents and famous guests. It was built during the Cold War to protect the US Congress in the event of a nuclear attack. The bunker was designed to house all 535 members of Congress and their staff for a long time.

This classified underground facility remained a secret until 1992, when a Washington Post article exposed it. Today, visitors can take tours to see special rooms, blast doors, and decontamination areas.

7

The Caverns

Image: jymy duhomme

Would you attend a concert underground? If you travel to Tennessee is totally possible! The Caverns, formerly known as Bluegrass Underground, is a very cool spot in Grundy County, Tennessee. Lying deep in a cave 333 feet underground, this concert venue with natural acoustics is the perfect place for live music.

People come from all over to hear a variety of performances, especially Bluegrass music. The Caverns can accommodate up to 1,200 people standing up and are equipped with state-of-the-art sound and lights. The cave's cool and quiet atmosphere makes the experience extra special!

8

Crystal City Underground

Image: Gustavo Alejandro Espinosa Reyes

Beneath the neighborhood of Crystal City, near Washington, DC, lies a network of shops, restaurants, and offices. It opened in 1976 and was designed to feel like an old shopping village with cobblestone streets and antique glass windows.

The underground space covers 150,000 square feet and connects several buildings. It's a popular spot for office workers and visitors, especially when the weather is bad. Unfortunately, in 2024, the shops closed, ending their retail era. Yet, the underground walkways and connections to the Metro remain open for pedestrians.

9

Los Angeles Prohibition Tunnels

Image: Alpha Perspective

In the 1920s, during Prohibition, people had to find ingenious ways around the restrictions on selling and consuming alcohol. That's why they built about 11 miles of underground tunnels right under Los Angeles.

Many of these subterranean sites are now closed, but you can still find a few hidden entrances around the city. You can even go on a tour to explore the tunnels and learn about their secret history.

10

Havre Beneath the Streets

Image: Đào Việt Hoàng

After a big fire in 1904 destroyed Havre’s business district in Montana, many shops moved underground. They used the old steam tunnels to stay safe from fires and bad weather. For years, the tunnels were busy with people and stores, such as saloons, drugstores, laundromats, and even a brothel. But today it is completely silent.

Fortunately, you can still visit what is left of this hidden city to see old shops and learn how people stayed safe and worked over 100 years ago. It's like going back in time!

11

Cheyenne Mountain Complex

Image: See page for author, Public domain, via Wikimedia Commons

One of the safest places in the world is right here in America, more specifically in El Paso County, Colorado. Hidden inside a mountain, Cheyenne Mountain Complex was built in the 1960s to protect the US military from nuclear attacks.

The bunker stands under 2,000 feet of solid Granite, making it super strong and safe. It was once the command center for NORAD (North American Aerospace Defense Command). The complex has blast doors that weigh 25 tons each and can withstand a nuclear blast. It also has its own power, water, and food supply. People could survive there for months!

12

Forestiere Underground Gardens

Image: Levi Clancy, CC0, via Wikimedia Commons

A Sicilian immigrant called Baldassare Forestiere spent 40 years digging and building a series of subterranean structures by hand in Fresno, California. Inspired by Roman catacombs and old wine cellars, he created around 65 rooms, tunnels, and courtyards to escape the hot summer sun.

The Gardens have fruit trees, grapevines, fishponds, and even a chapel. Some of the trees are more than 90 years old! Today, Forestiere Underground Gardens is a Historical Landmark you can visit if you want to discover a true underground paradise.

1

Tennessee - Cotton candy

Cotton candy feels like pure fun, which makes its origin even better. A Nashville dentist helped invent the machine that turns sugar into fluffy clouds. It debuted at the St. Louis World’s Fair and became a carnival favorite. Genius way to get more patients on his chair, huh?

2

Georgia - Coca-Cola

In an Atlanta pharmacy in 1886, John Pemberton mixed up a syrup meant to be medicinal. It included coca leaf extract and kola nuts and was sold as a tonic. The drink evolved quickly, lost its medical claims, and became Coca-Cola. The rest is simply history!

3

New Jersey - Light bulb

This one is a classic! In Menlo Park, Thomas Edison built a laboratory that became an invention factory. There, a commercially viable incandescent light bulb was developed. While this gets most of the applause, that same New Jersey workspace also helped shape recorded sound and motion pictures.

4

Indiana - Rearview mirror

At the very first Indianapolis 500, one driver decided he did not need someone sitting behind him to watch traffic. Can you imagine how uncomfortable a job that was? Ray Harroun instead attached a mirror to his dashboard. That simple choice helped him win the race and changed driving for everyone.

5

California - Jeans

Rugged work pants were falling apart under hard labor until rivets entered the picture. A tailor named Jacob Davis teamed up with Levi Strauss in San Francisco to reinforce trousers for miners . Denim soon followed, and jeans became a global staple. From gold fields to casual Fridays, the look never left.

6

Ohio - Traffic light

Cleveland inventor Garrett Morgan noticed a deadly problem at busy intersections . His improved traffic signal added a pause that stopped all directions before letting cars move again. That brief moment of calm saved lives and brought order to chaos.

7

Missouri - Ready mix

Pancakes once meant measuring flour, salt, and patience. In 1889, Missouri innovators created one of the first commercially successful ready mixes under the Aunt Jemima name . Pour, add liquid, and cook. It reshaped home kitchens and paved the way for countless boxed mixes.

8

North Carolina - Vicks VapoRub

A Greensboro pharmacist created dozens of remedies, but one stood out. His menthol ointment eased breathing and comforted countless families. Rebranded as Vicks VapoRub, it became a staple in every medicine cabinet.

9

Wisconsin - Blender

The first motor-powered blenders came from Wisconsin, even if they needed a little help to work properly. Once refined, they became the Waring Blendor and found their way into diners, homes, and smoothie shops. Nowadays, they are a household essential; even kids know how to work one!

10

Oklahoma - Parking meter

Crowded streets needed turnover, so Oklahoma City tried something new. The parking meter encouraged drivers to move along and freed up spaces for shoppers. Love them or hate them, parking meters changed how cities function.

11

New York - Toilet paper

Toilet paper feels like it has always been around, but it hasn’t. In 1857, a New Yorker named Joseph Gayetty introduced paper designed specifically for bathroom use . His marketing was not so effective, but the idea stuck. Before that, people relied on catalogs and newspapers. Thank you, New York!

1

Olympic National Park, Washington (2.9 million visitors)

Located in Washington state, in the Pacific Northwest, this park offers a mix of glaciated mountains, lush rainforests, lakes, rivers, and more than 70 miles of coastline . Established as a national monument in 1909, it was designated a national park in 1938 by President Franklin D. Roosevelt.

2

Joshua Tree National Park, California (3.2 million visitors)

Famous for the Joshua trees that give it its name, this area was designated a national monument in 1936 and a national park in 1994. The park encompasses part of two California deserts —the Mojave and Colorado deserts—and is lined by the Little San Bernardino Mountains in the southwest.

3

Grand Teton National Park, Wyoming (3.4 million visitors)

Did you know that most of this national park exists thanks to an oil magnate? The park was established in 1929, but it was enlarged when John D. Rockefeller Jr. —who also contributed to many other national parks— secretly purchased surrounding land to be established as a monument. The park gets its name from the tallest peak of the Teton mountain range , and it's famous for its pristine lakes and abundant wildlife.

4

Acadia National Park, Maine (3.8 million visitors)

Located on the Maine coast, this park was established as a national monument in 1916 and a national park in 1919. Besides the beautiful Atlantic shoreline, Acadia National Park offers granite mountain peaks, forests, lakes, and islands .

5

Yosemite National Park, California (3.8 million visitors)

Famous for both its granite peaks and its tall sequoias, Yosemite National Park is located in the Sierra Nevada range in California . Established in 1890, some of its popular features are the El Capitan —a tall rock formation— the Cathedral Peak, and the Sentinel dome.

6

Rocky Mountain National Park, Colorado (4.1 million visitors)

Located within the Front Range of the Rocky Mountains, it was established in 1915 by President Woodrow Wilson. Besides its stunning mountain views and alpine lakes, the park is home to the Trail Ridge Road , one of the highest paved routes in the country.

7

Yellowstone National Park, Wyoming, Montana, and Idaho (4.5 million visitors)

Considered to be the first national park in the world, Yellowstone was established in 1872 and covers part of three different states —Wyoming, Montana, and Idaho. Besides its wildlife and mountain scenery, it is famous for being located in a volcanic caldera and having many geothermal features. The most famous among them is the Old Faithful geyser.

8

Zion National Park, Utah (4.6 million visitors)

Located in Utah, where the Colorado Plateau, the Great Basin, and the Mojave Desert meet, this national park boasts a hugely diverse ecosystem , with varied plants and animals. Its geography includes mountains, canyons, buttes, mesas, and monoliths, including the famous Zion Canyon. The park was established in 1919.

9

Grand Canyon National Park, Arizona (4.7 million visitors)

Centered around one of the most famous landmarks in America , this national park was established in 1908 as a national monument and designated a national park in 1919. The Grand Canyon, carved by the Colorado River in the Arizona desert, was designated a World Heritage Site by UNESCO.

10

Great Smoky Mountains National Park, North Carolina and Tennessee (13.2 million visitors)

Straddling the North Carolina-Tennessee border, this national park not only includes part of the Great Smoky Mountain range, but also the Blue Ridge Mountains and the Appalachian rainforest. Established in 1934 by Franklin D. Roosevelt, this park is the home of some of the tallest mountains of eastern North America , such as Kuwohi or Mount Guyot.