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

Jackson, Mississippi

Image: Engineers' office, department of Tennessee, Public domain, via Wikimedia Commons

Did you know Jackson, Mississippi, is named after the 7th U.S. President, Andrew Jackson? It is one of the four state capitals named after American presidents —the other three are Jefferson City (Missouri), Lincoln (Nebraska), and Madison (Wisconsin).

Jackson is the only U.S. capital built on top of an extinct volcano. Interestingly, during the Civil War, the city was burned by Union troops, giving it the nickname "Chimneyville". In addition, Jackson is best known for being the center of the civil rights movement during the 1950s and 1960s.

2

Santa Fe, New Mexico

Image: Wendy Shervington

In 1610, Spanish settlers established Santa Fe as the capital of New Mexico, making it the oldest state capital in the country. But that's not the only peculiarity of this quaint city with a temperate climate and a unique historical and cultural richness. At 7,000 feet above sea level, Santa Fe is also the highest U.S. capital.

3

Honolulu, Hawaii

Image: Daniel Lee

Known for its spectacular beaches and rich cultural heritage, Honolulu is the only state capital not on the North American mainland. Considered the birthplace of modern surfing, it also has the highest average annual temperature of any U.S. state capital.

But those aren't the only interesting facts about Hawaii's capital. Here are a few equally (or more) crazy ones: it hosts the only royal palace in the United States (Iolani Palace), the island is made up of volcanic soil, and it houses the world's largest open-air shopping mall (Ala Moana Center).

4

Annapolis, Maryland

Image: Terry Granger

Annapolis is a historic city on the shores of the Chesapeake Bay, known for its colonial architecture, nautical tradition, and academic value. But did you know it is also the smallest U.S. capital by land size? Just 6.7 square miles!

Annapolis was also one of the nine capitals the United States has had throughout its history. For nine months during the Revolutionary War, Maryland's current state capital served as the seat of the Confederation Congress.

5

Bismarck, North Dakota

Image: NASA Astronaut, Public domain, via Wikimedia Commons

If you thought Juneau, Alaska, had the lowest average winter temperature of all state capitals, think again! It's actually Bismarck, North Dakota, where the coldest temperature ever recorded was -45°F. Imagine that!

Bismarck was founded in 1872 on the banks of the Missouri River. The city was named after Otto von Bismarck, the chancellor of Germany, to attract German investors. Another fun fact? In 1930, Bismarck and Fargo had a dispute, known as the "Capitol Tower War," over which city should be the state capital.

6

Charleston, West Virginia

Image: Carol M. Highsmith, Public domain, via Wikimedia Commons

Did you know that the original name of West Virginia's capital was Charles Town in honor of the father of Colonel George Clendenin, one of the first settlers?

Charleston is best known for offering a unique combination of history, culture, and outdoor adventure.

7

Hartford, Connecticut

Image: Balazs Busznyak

Founded in 1635, Connecticut's capital is one of the oldest cities in the U.S. Hartford is known for being a key cultural center in New England. It was the home of writer Mark Twain and is home to historic sites such as the State Capitol, the Harriet Beecher Stowe House, and Bushnell Park, the oldest public park in the country.

Hartford is also called the "insurance capital of the world" due to the presence of major insurance companies. But the city's most curious fact is that it was where Teddy Roosevelt, aboard the Columbia Electric Victoria Phaeton, took the first presidential automobile ride in history!

8

Harrisburg, Pennsylvania

Image: Katherine McAdoo

Pennsylvania's capital city is best known for its role in the Civil War and the Underground Railroad. Located on the banks of the Susquehanna River, Harrisburg has been an important center of transportation and commerce. Today, it is known for its historic architecture, museums, and special events.

Harrisburg is also home to the longest stone arch bridge in the world, the Rockville Bridge, built in 1902. Oh, and in 1979, it came close to a nuclear disaster due to the accident at the Three Mile Island plant, the worst in U.S. history —but that's a longer story for another article!

9

Olympia, Washington

Image: Peter Robbins

Located at the southern tip of Puget Bay, Washington's state capital is known for its natural beauty and vibrant culture. But did you know Olympia is the northernmost state capital in the contiguous U.S.?

Oh, and it's also a great place to try some of the best craft beer in the country!

10

Salt Lake City, Utah

Image: Cong Wang

Utah's state capital is popular for being one of the best places to ski in the United States. But that's not all! Salt Lake City is also the only state capital with three words in its name. Have you ever thought about that?

It has the largest Mormon population in the country and is the world headquarters of the Church of Jesus Christ of Latter-day Saints. Another fun fact? Salt Lake City is home to more plastic surgeons per capita than any other state capital!

11

Montpelier, Vermont

Image: John Holm

Named after the French city of the same name, Montpelier is the least populated state capital, with a population of just 7,900. Probably for that reason, Vermont's capital prides itself on its small local businesses: it is the only state capital that doesn't have a McDonald's or a Starbucks. Could you live without these fast food chains? It doesn't have a Walmart store either!

12

Topeka, Kansas

Image: Nils Huenerfuerst

Topeka, Kansas’s state capital, has several interesting tidbits. For example, did you know its name, of Native American origin, means "a good place to dig potatoes"? Interesting, don’t you think?

In 2010, Topeka temporarily changed its name to "Google, Kansas" to attract the attention of the internet giant and become the capital city of fiber optics. Frivolous facts aside, Topeka was also very important in the history of the civil rights movement.

1

Arizona skips Daylight Saving Time

Image: Christoph von Gellhorn

This is partly true because most of the state doesn’t bother with Daylight Saving Time . They stopped changing the clocks back in 1967. The exception is the Navajo Nation, which stretches into Utah and New Mexico and keeps DST so all its communities stay on the same schedule. Now, as for the smaller Hopi reservation, inside the Navajo Nation, it sticks with Arizona time… Yes, quite confusing if you’re not a local.

2

Georgia isn’t really the Peach State

Image: Jessica Furtney

Georgia loves its peaches, sure, but the state’s top fruit money-maker is actually blueberries . In recent years, blueberries have brought in several times more cash for farmers than peaches. Meanwhile, California grows far more peaches than Georgia ever has. The nickname stuck from the old days when Georgia peaches were famous for their flavor, not their volume. So while the pride is real, the peaches aren’t quite the powerhouse people may think.

3

Nevada didn’t record the hottest US temperature

Image: tommao wang

You probably think of Nevada’s desert heat as unmatched, but the all-time record belongs to California’s Death Valley . In July 1913, it hit a mind-melting 134 degrees Fahrenheit, the hottest temperature not only in America but the hottest ever recorded on Earth!

4

Minnesota doesn’t have the most lakes

Image: Tom Conway

Minnesota proudly calls itself the "Land of 10,000 Lakes," but that’s selling itself short… The real number is closer to 12,000. However, Alaska wins this battle . The state has more than 3 million lakes over five acres in size. In fact, Alaska contains over 40 percent of the nation’s surface water. If you love fishing, kayaking, or just staring at a quiet stretch of water, the true lake capital of America is far up north.

5

Pineapples aren’t native to Hawaii

Image: Christian Joudrey

Pineapples are everywhere in Hawaiian imagery, but the plant actually comes from South America , mainly Paraguay and southern Brazil. Spanish explorers likely brought them to Hawaii in the 1500s after spreading them across the Pacific to places like the Philippines and Guam. Hawaii’s climate turned out to be perfect for growing them and by the 1900s, the islands were producing so many pineapples that the fruit became a symbol of Hawaii itself.

6

Maine isn’t the country’s easternmost point

Image: Chris Henry

If you’re a Geography geek, you’ll love this one. You might picture Maine’s rocky coast as the eastern tip of America, but the actual easternmost point is thousands of miles away, on Alaska’s Semisopochnoi Island in the Aleutians. How is that possible? Well, that’s because it crosses the 180th meridian, putting it in the Eastern Hemisphere. That means part of Alaska technically sits farther east than anywhere in Maine.

7

The biggest US earthquake didn’t happen in California

Image: Lala Miklós

California has suffered some big earthquakes in its history, but the most powerful earthquake in America struck Alaska in 1964 . It hit Prince William Sound with a magnitude of 9.2. It was so strong it shook the ground for four and a half minutes and triggered massive tsunamis. In today’s dollars, the damage would total more than $2 billion. Alaska sits on a collision zone of tectonic plates, making it one of the world’s most seismically active regions.

8

The Everglades isn’t America’s biggest swamp

Image: Joshua J. Cotten

A lot of people picture the Florida Everglades when they think of swamps, but technically, the Everglades isn’t a swamp at all. The real title of the largest swamp in the United States goes to Louisiana’s Atchafalaya Basin , which spans about 1.4 million acres. This swamp has a vast mix of cypress forests, bayous, and marshes, and it’s more than twice as productive as the Everglades when it comes to wildlife and plant life.

9

Big cities aren’t always capitals

Image: Mackenzie Cruz

It surprises people how often the biggest city isn’t the state capital . New York City? Not the capital… Albany is. Chicago? Nope, that honor goes to Springfield. Pennsylvania’s capital isn’t Philly or Pittsburgh, it’s Harrisburg. Even California’s capital isn’t L.A. or San Francisco, it’s actually Sacramento. Out of fifty states, only seventeen have their most populous city as the capital.

10

Alaska isn’t divided into counties

Image: Rod Long

Alaska likes to do things its own way. Instead of counties, it’s split into boroughs , and a massive area known as the Unorganized Borough has no local government at all. People out there don’t pay property taxes, but that freedom comes with challenges, limited services, fewer job options, and tough living conditions.