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

Being annoying

We all have bad days where our mood goes south, but in Florida, you’d better keep those frustrations to yourself . Ever since 1832, the Sunshine State has had a broad nuisance statute that classifies anything that "annoys the community, injures public health, or corrupts public morals" as a second-degree misdemeanor. Of course, the law was intended to address community hazards like toxic waste disposal or unsafe buildings. Modern enforcement targets environmental hazards and serious health violations. Personal annoyances are off-limits, since what qualifies as "annoying" is completely subjective.

2

Honking with no purpose

We’ve all used our car horn to wave at a neighbor or used it to vent a little frustration in traffic. However, in New Jersey, according to their traffic code, your horn is legally reserved for safety warnings only . In this state, using it for any non-emergency reason is technically a traffic violation since 1968. Unless you are trying to prevent a fender-bender or warn a distracted driver, it is best to keep your hands off the steering wheel's center and just give a friendly wave instead.

3

Dangling car decorations

If you have a pine-scented air freshener or a set of graduation tassels swinging from your rearview mirror, you might be looking at a ticket in some states. Laws vary across the country, but for example, in California, the law states that there cannot be anything obstructing the view through the windshield or side window . This rule is part of the California Vehicle Code, enforced in 1959. In Texas, the regulation is similar according to the state Transportation Code, and Minnesota, in turn, has had a law since 1957 making it strictly illegal to hang anything from the mirror. Nobody has anything against a nice-smelling car or a beautiful lucky charm, but when they obstruct your view , that’s a problem for everyone on the road.

4

Handling a stranger’s mail

It’s not unusual to find a stack of letters addressed to the person who lived in your house three years ago, right? Now, your first instinct might be to toss it in the bin . Believe it or not, that’s a big no-no since 1948, clearly stated in the U.S. Code. Tossing out mail intended for someone else into the garbage is considered a federal felony, and penalties can be severe, including up to five years in federal prison and fines up to $250,000. The proper way to proceed is to write "refused" or "return to sender" on the envelope and let the post office take it from there.

5

Forgetting to tell the DMV you moved

Life gets busy and messy when you move to a new house, so it’s easy for updating your driver's license to fall to the bottom of the to-do list. However, in most states, you are legally required to notify the DMV of your change of address within a very short window, usually ten to thirty days . In California, for example, you must do this within ten days. If you get pulled over and your license doesn't match your current address, you could get a fine. Time really flies when moving, but make sure to write this on the very top of your to-do list, and you’ll be fine!

6

Letting the engine on

Isn’t it common to start the car on a frosty morning to let it warm up while you finish getting ready? Well, if you do this, you’re technically breaking the law in some states: since 2004, in Ohio and Colorado, this is actually a citable offense known as "puffing." Leaving an unattended vehicle idling in your driveway is illegal because it invites car theft and contributes to unnecessary exhaust emissions. If you want to get the heater going, the law expects you to stay right there in the driver's seat until you’re ready to pull away.

7

Prank pizzas

In Louisiana, ordering a stack of pizzas to be delivered to an unsuspecting friend as a prank is more than just a lousy joke; it’s a crime. Believe it or not, there’s a reason behind this law. Passed in 2018, the Louisiana Revised Statute was specifically written to protect small businesses from losing time and money on fake orders. Can you imagine how annoying it must be to deal with a pranked customer who doesn’t want the five pizzas they got out of the blue? Even if it started as a joke, the authorities now view it as a form of theft that can result in a fine of up to $500, imprisonment for up to six months, or both.

8

Playing hairdresser

If you’ve ever offered to give a friend a quick perm or some highlights in your kitchen, you might be an accidental criminal. In the US, performing any kind of cosmetology service on another person without a professional license is illegal. Forms of enforcement and penalties depend on each state, but most follow the rules established by the National-Interstate Council of State Boards of Cosmetology, which grants licenses following pertinent examinations. Of course, a bangs cut is not always a problem, but these kinds of regulations were created to ensure that chemicals and sharp tools are handled safely by trained experts.

9

No-hands bike riding

Riding a bike is fun, especially for kids who like to do tricks and take both hands off the handlebars. But in North Carolina, that’s a traffic violation, according to the city code. The statute requires cyclists to keep at least one hand on the grip at all times to maintain control of the bike. Fines for this behavior can go up to $50 and even imprisonment for up to 30 days. Riding a bike without using your hands might feel like a fun way to show off skills, but the consequences can be serious.

10

Tossing out old batteries

When the remote dies, most people are tempted to just drop the old batteries into the kitchen trash can, but you might want to think that over, especially if you live in California. As of 2005, in this state, household batteries are classified as hazardous waste because they contain chemicals that leak into the soil. The California Rechargeable Battery Recycling Act requires you to take them to a proper recycling center instead of the regular landfill. It takes a little more effort to do the right thing, but it keeps the local environment a lot cleaner for everyone.

11

Lending your Wi-Fi password

You’ve just moved, and you ask your friendly neighbor to share their Wi-Fi password until your internet is set up. That’s pretty common, but that’s also been a felony since 1986. The feds view this as unauthorized access to a computer network . Under the Computer Fraud and Abuse Act, jumping on a signal you don't have explicit and formal permission to use is technically a crime. It’s better to stick to the local coffee shop than risk a run-in over a bit of borrowed bandwidth.

1

A Presidential curse

For almost 140 years, U.S. presidents elected in years ending in zero died while in office. It happened to William Henry Harrison (1840), Abraham Lincoln (1860), James A. Garfield (1880), William McKinley (1900), Warren G. Harding (1920), Franklin D. Roosevelt (1940), and John F. Kennedy in 1960 . Ronald Reagan, elected in 1980 , broke the curse by surviving an assassination attempt.

2

Mark Twain and Halley’s Comet

In the year Mark Twain was born, 1835, Halley’s Comet passed by Earth. The great writer famously predicted he’d "go out with it" as well . Indeed, he passed away in 1910, the next time the comet appeared.

3

Jefferson and Adams

A patriotic yet somber coincidence, indeed. John Adams and Thomas Jefferson, the second and third U.S. presidents, both died on July 4, 1826 —exactly 50 years after the signing of the Declaration of Independence.

4

Hoover Dam’s first and last casualties

The construction of the Hoover Dam was a long and difficult process, claiming over 100 lives. The first person to die was J.G. Tierney , and the last recorded death was his son , Patrick Tierney.

5

Lincoln and Kennedy

Abraham Lincoln and John F. Kennedy were elected 100 years apart (1860 and 1960). Both suffered fatal head wounds and were succeeded by presidents named Johnson. Their assassins each had three names: John Wilkes Booth and Lee Harvey Oswald. Both were assassinated on a Friday while sitting next to their wives at the time that it happened.

6

Charles Francis Coghlan’s last journey

Actor Charles Francis Coghlan died in Texas in 1899. But his casket was lost at sea during a hurricane. Eight years later, his coffin washed ashore near his birthplace in Prince Edward Island, Canada, more than 3,000 miles away.

7

The Titanic coincidence

A few years before the Titanic sank, Morgan Robertson wrote a short book called Futility , about a massive "unsinkable" ship called the Titan that hit an iceberg and sank. The tale describes a ship with a similar size and a similar lack of lifeboats to the famous vessel.

8

Dennis the Menace

Two comic strips featuring a character named Dennis the Menace debuted in British and American outlets, respectively, on March 12, 1961—only a few hours apart. However, the two creators did not know each other and had no idea of the other’s work.

9

Jim Lewis and Jim Springer

Identical twin brothers separated at birth , Jim Lewis and Jim Springer, were reunited at age 39 and discovered many coincidences: both married women named Linda , divorced, and then remarried women named Betty. Both had dogs named Toy and drove the same model of car. Both grew up with an adopted brother named Larry and had sons whom they named James Allan.

10

Disney magic

A soon-to-be-married couple, Alex and Donna , were looking through old photos to include in their wedding video. They found one photo of Donna posing on a childhood trip to Disney World in 1980. And in the background, they spotted Alex being pushed in a stroller by his father.

11

Moped meets taxi, twice

In 1975, 17-year-old Erskine Lawrence Ebbin was struck by a taxi in Bermuda while riding his moped. A year later, his brother Neville , also 17 at the time, was riding the same moped when he was struck by the same taxi —with the same passenger—on the same street.

12

Lightning strike survivor

Being hit by lightning is an extremely rare occurrence. Park ranger Roy Sullivan was struck not once, but seven times between 1942 and 1977 —and survived them all. The strikes hit him in a fire tower, in his truck, in his yard, while patrolling, and more. His unusual record earned him the nickname "Human Lightning Rod."