1

National Mall’s hidden tunnel (Washington, DC)

The National Mall landscape in Washington, DC, is so familiar that it’s hard to imagine anything hidden beneath it, but there is more going on below the surface than most visitors realize.

Beneath parts of the Mall, a network of underground tunnels connects buildings like the Smithsonian Institution Building, a.k.a "The Castle", with other Smithsonian facilities, including the National Museum of Natural History. They’re mainly used for utilities, secure staff access, and behind-the-scenes operations that keep the museums running smoothly.

2

Mount Rushmore’s secret chamber (Keystone, SD)

When you look at Mount Rushmore, the first thing you notice is the four faces of George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln, but there’s more than meets the eye. Hidden behind Lincoln’s head is a secret chamber known as the "Hall of Records," a place visitors have rarely ever seen. It was the idea of sculptor Gutzon Borglum, who imagined it as a grand room to hold important US documents and tell our story as a country. Construction began with that goal, but the project was never completed. Today, the chamber remains unfinished, but it's there, waiting to be visited someday.

3

The Las Vegas sign is in another city (technically, Paradise, NV)

Do you have the classic picture in front of the iconic "Welcome to Fabulous Las Vegas" sign? If you snapped it and then drove to another city, we hate to break it to you, but you weren’t in Las Vegas.

The famous sign, installed in 1959, actually sits a couple of miles outside the city limits. In fact, the sign and most of the Strip are technically located in the towns of Paradise and Winchester, unincorporated communities in Clark County, Nevada, not within Las Vegas itself. And that’s no accident: much of the Strip and its casinos were originally developed outside the city in the 1950s to avoid municipal taxes and regulations.

4

Fragments of the Antarctic ice sheets (Denver, CO)

Did you know that the Mile High City stores miles of ice from Greenland and Antarctica? Ok, but how?

At Denver’s National Ice Core Laboratory, part of the Federal Science Center, the ice is kept at around -32.8°F. Researchers study it not just to understand Antarctica itself, but also to inspect Earth’s history. Some of these blocks of ice are hundreds of thousands of years old, and from them, scientists can reconstruct ancient temperatures, track greenhouse gas levels, and even identify major volcanic eruptions preserved in the layers.

5

The hatch at the top of City Hall Tower (Philadelphia, PA)

Counting the statue of William Penn at its summit, the tower of Philadelphia City Hall rises about 548 feet, making it the tallest municipal building in the United States. But hidden high above the street, the statue conceals a little-known secret.

At its base is a small hatch, originally built to give workers access for maintenance. It offers an incredible vantage point over the city, but getting there isn’t easy. To reach it, you have to climb narrow stairways and walk through tight, elevated passageways. Would you dare give it a try?

6

A 112,544 square-foot underground bunker (White Sulphur Springs, WV)

The tense atmosphere and threats of the Cold War led to the construction of thousands of underground bunkers across the US. And one of the most impressive is right beneath the Greenbrier Resort in White Sulphur Springs, West Virginia.

Buried 720 feet into the hillside, this 112,544-square-foot bunker was created to shelter all 535 members of the US Congress in the event of a nuclear attack. Built between 1958 and 1961, it was sealed behind a 25-ton blast door, and it remained a protected secret for more than 30 years.

7

Catacombs underneath City Market (Indianapolis, IN)

In downtown Indianapolis, the City Market has been a gathering place since 1886, filled with local vendors, cafés, and shops. But there’s more to it than what you see above ground. Beneath the market lies a network known as the City Market’s "catacombs."

Despite the name, the reality isn't quite so macabre; they’re a series of brick archways that once supported Tomlinson Hall, a huge market building demolished in the mid-20th century. Today, this underground space remains as a hidden piece of the city’s past, but unlike many places on this list, it’s occasionally open for guided tours.

8

One of history's biggest art heists (Boston, MA)

We all know Boston as the "birthplace of the American Revolution," home to events like the Boston Massacre and the Boston Tea Party. But there’s another chapter of its history you don’t hear about as often.

Just over 30 years ago, Boston was the scene of one of the biggest art heists in history. In the early hours of March 18, 1990, two men disguised as police officers entered the Isabella Stewart Gardner Museum, overpowered the guards, and stole 13 invaluable works of art, including pieces by Vermeer, Degas, Rembrandt, and Manet. To this day, the case remains unsolved, and a multi-million-dollar reward is still offered for information.

9

One of the quietest places on Earth (Minneapolis, MN)

Where do you think the quietest places on Earth are? You might imagine remote landscapes far from civilization, but one of them is actually right in Minneapolis, Minnesota.

Inside Orfield Laboratories, there’s a room with no windows or natural light, an anechoic chamber that absorbs nearly all sound. That’s right: it blocks almost every noise, making the space even quieter than a vacuum. Visitors say the silence is so intense that you can hear your own heartbeat and even the faintest movements of your body. Simply incredible.

10

A strange law (Los Angeles, CA)

Why would a city actually pass an ordinance saying that licking toads is a bad idea? That’s Los Angeles, a place full of quirks, some charming, some downright strange. Even its laws can be unusual.

The Colorado River toad, found in parts of California, secretes chemicals that can have powerful psychoactive effects on humans. Because of the risks, both possession and use of this substance are illegal statewide. In 1994, cases occurred, including a teacher who was arrested for possessing the toad substance. But Los Angeles went a step further, passing an ordinance that specifically bans licking these amphibians. And let’s be honest, the poor toad probably doesn’t enjoy it either.

1

Point Roberts, WA: The 49th parallel accident

Imagine if you had to cross two borders just to get to the market for a gallon of milk. That’s actually a reality for residents of Point Roberts, Washington. That’s because, following the Anglo-American Convention of 1818, the 49th parallel divided Canada and the U.S. In 1846, the line was extended westward and then officially recognized by the International Boundary Commission in 1925.

However, a tiny tip of the Tsawwassen Peninsula poked out just below that line. Since then, the locals have lived in a boundary quirk. To get to the rest of Washington State by land, they must drive through Canada, show their passports, and do it all over again on the way back.

2

Statue of Liberty: Common misconception

If you want to start a friendly argument at a dinner party, ask whether the Statue of Liberty lives in New York or New Jersey. The funny thing is, both answers are technically right . While the statue physically sits in the waters of the Garden State, Liberty Island is legally an exclave of New York. This dates back to a 1664 land grant by the Duke of York in a document so vague and confusing that it took a 1834 Compact between the two states to settle the deal. New Jersey gets the water and the submerged lands, but New York keeps the monument.

However, the Federal Government actually manages the site through the National Park Service (NPS), providing security and maintenance.

3

The State of Franklin: Failed 14th state

If you think Tennessee was the 14th state to join the Union, there’s a catch. Before Tennessee, there was Franklin. In 1874, three counties in North Carolina felt neglected by their government and decided to strike out on their own . They even elected a governor, John Sevier, and printed their own money. They came just two votes short of being recognized by Congress as a formal state. Eventually, things got heated, and North Carolina sent troops, leading to a small civil war between the locals. By 1879, the dream of Franklin was dead and buried, and the territory became part of Tennessee.

4

Kentucky Bend

If you look closely at a map, there’s a piece of Kentucky that looks like it doesn’t belong. That’s the Kentucky Bend, also called the New Madrid Bend, a tiny peninsula in Fulton County that is almost completely separated from the rest of the Bluegrass State . The strange situation was the consequence of the massive series of earthquakes that took place in that area between 1811 and 1812, which were so violent they famously caused the Mississippi River to flow backwards for several hours. When the dust settled, the river had carved a new path that looped around this small patch of land, surrounded by Missouri and Tennessee instead of Kentucky. The 9 residents living there today go through Tennessee just to get to their home state.

5

The State of Deseret: The empire that almost was

Imagine a state so big it makes Texas look tiny. That almost happened back in 1894, when Mormon pioneers proposed the State of Deseret. The territory comprised what we now know as Utah, most of Nevada, parts of Arizona and Colorado, and a massive chunk of the California coast, including San Diego.

Had it been formalized, it would have been a powerhouse with its own seaport and total control over the West. However, Washington, D.C. wasn’t so keen on one group having that much territory and power, so they whittled it down, and we ended up having the states we know today.

6

The lawless "No Man's Land"

Have you ever wondered what happens when two governments simply give up on a piece of land? Between 1806 and 1821, there was a strip of land in what is now western Louisiana that was, literally, No Man’s Land. Neither the U.S. nor Spain, which owned part of the territory, could agree on the border, so they declared it "Neutral Ground" to avoid armed conflicts . The plan backfired as, with no laws to contain it, it quickly became a favorite for the outlaws in the West —meaning deserters and bandits hiding there were legally untouchable. The conflict was resolved by the 1819 Adams-Onis Treaty, which officially set the Sabine River as the legal boundary.

7

The Republic of the Indian Stream

In the early 1830s, people living in a small area between New Hampshire and Quebec were fed up, and in this case, taxes were the problem. Both Canada and the US were trying to collect taxes, and nobody likes being double-billed . In 1832, the residents essentially said "neither of them can tax us" and formed their own country called the Republic of the Indian Stream. They had their own constitution and Capitol for four years, until 1836, when the militia marched on the disputed territory to reclaim the land. It wasn’t until 1842, when the land dispute and the double-taxation was definitively resolved by the Webster–Ashburton Treaty, which assigned the land to New Hampshire.

8

The Northwest Angle: Mapping mistake of 1783

When the Treaty of Paris was signed in 1783 to end the Revolutionary War, the mapmakers used a chart that was flat-out wrong. They thought the Mississippi River started much further north than it actually did. Because of that mistake, a piece of Minnesota got cut off from the rest of the country . To this day, the "Northwest Angle" is the only place in the lower 48 states north of the 49th parallel. Much like Point Roberts, you have to cross a massive lake or drive through Canada just to visit it.

9

The District of Columbia’s "lost" corner

If you look at a map of D.C., you’ll notice it’s missing a chunk; it’s not a perfect square as it was originally intended. Originally, the capital was a perfect ten-mile square diamond , taking land from both Maryland and Virginia. But by 1846, things got tense. Residents in the Virginia portion, which included Alexandria and Arlington, were worried the federal government would abolish slavery in the District, which was the backbone of their economy. They successfully petitioned to have Virginia "take back" that portion of the land and subsequently changed the shape of the national capital forever.

10

UN Headquarters: International territory

If you want to feel international, go to the United Nations Headquarters on the East River in midtown Manhattan, New York. Once you cross that gate onto the 18-acre site, you are technically leaving the United States. You don’t need to show your passport, but that’s international territory, which means it has its own laws , its own security force, and even its own postal service. It is a legal hole in the middle of New York City.

1

It was invented in Switzerland

While the name suggests a US origin, the technology that created American cheese actually began in the heart of the Alps. It was developed in 1911 by Swiss researchers Walter Gerber and Fritz Stettler, who were looking for a way to extend the shelf life of their country’s famous Emmental cheese.

The problem with traditional cheese is that it eventually dries out, molds, or separates into a greasy mess when heated. By shredding the cheese, adding sodium citrate, and heating it, the Swiss duo discovered they could create a stable, smooth product that didn't separate. While they weren't trying to create "American" cheese as we know it today, their emulsification process laid the foundational science for every single-wrapped slice produced today.

2

It was popularized by a Canadian

The man responsible for the global dominance of American cheese was James L. Kraft. Ring any bells? Kraft was a Canadian immigrant who moved to Chicago in 1903. While he didn't invent the concept of processed cheese, he perfected the industrial scale of its production and marketing.

Kraft noticed that retailers struggled with cheese spoilage; if a wheel of cheddar didn't sell quickly, it was a total loss. He experimented with various methods of heating and blending cheese until he found a formula that could be canned and shipped long distances without spoiling. In 1916, he received a patent for his "processed cheese," and during World War I, the U.S. government purchased millions of pounds of it for soldiers, cementing its privileged place in the American diet.

3

It was almost called "Embalmed Cheese"

When processed cheese first hit the market, it had its detractors. Traditional cheesemakers were horrified, and so were pure food advocates. These critics argued that the product shouldn't even be called cheese. They’ve even gone so far as to call it "embalmed cheese" because of its unnaturally long shelf life and the chemical emulsifiers used to keep it stable. Yet, Kraft’s marketing prowess and the sheer convenience of the product ultimately won the naming battle. At least in the court of public opinion.

4

Technically, it isn’t cheese

Kraft may have won the battle among the people, but legally, American cheese is not considered cheese. If you look closely at the packaging, you will rarely see the word "cheese" on its own. Because of strict FDA regulations, most varieties are legally classified as "Pasteurized Process Cheese Product" or "Pasteurized Process American Cheese Food."

To be labeled "cheese," a product must be made primarily of milk, salt, and enzymes. Processed American cheese, however, is made by blending real cheese—usually cheddar or Colby—with emulsifying salts, whey, and sometimes extra milk or fats.

5

Any cheese can be made into American cheese

The term "American cheese" refers more to a process than a specific flavor. In theory, you could make "American-style" brie, blue cheese, or parmesan. The defining characteristic is the addition of an emulsifier, which breaks down the proteins and allows the fats and water to stay together.

In fact, some high-end chefs now make their own artisanal American cheese with aged cheddars processed with sodium citrate to create a slice that has the complex flavor of an expensive block but the melting point of a Kraft Single.

6

It isn’t naturally yellow

The vibrant orange-yellow hue of American cheese is entirely a cosmetic choice. Traditionally, cheese color varied by the season; when cows ate fresh grass in the summer, their milk contained more beta-carotene, leading to a naturally yellowish cheese. To make their cheese look high-quality all year round, cheesemakers began adding dyes.

American cheese takes this tradition to the extreme. It is typically colored with annatto, a seed from the achiote tree. Without this dye, American cheese would be a pale, creamy white, which is how it is sold in many delis as "White American". Yes, that’s right, there is no flavor difference between the white and yellow versions.

7

It has an extremely low melting point

The scientific superpower of American cheese is its meltability. Traditional cheeses have a protein structure that tightens when heated, which is why a slice of aged cheddar on a burger often results in an oily puddle and a rubbery clump.

Because of the emulsifying salts, the proteins in American cheese can withstand heat without clumping together. This gives it an incredibly low and stable melting point, transforming the slice into a silky sauce. This is why it remains the undisputed king of grilled cheese sandwiches.

8

It’s been in space

When you're hurtling through orbit in a cramped capsule, you need food that is stable, easy to eat, and won't crumble into thousands of tiny, electronics-clogging pieces. American cheese fit the bill perfectly for early NASA missions.

Processed cheese in tubes or cubes was a staple of the Apollo missions. Because it doesn't separate or sweat oil in varying temperatures and pressures, it was one of the few dairy products that could reliably provide flavor and calcium to astronauts.

9

It helped bring cheese to the masses

Before the advent of processed cheese, cheese was often a seasonal luxury. It was difficult to transport, expensive to store, and highly variable in quality. James L. Kraft’s invention changed that. By creating a product that was uniform in flavor and shelf-stable, he made cheese affordable and accessible to every corner of the United States.

10

The U.S. Government once gave it out

The U.S. government not only bought tons of American cheese during World War I. In the 1980s, the term "government cheese" became a thing. During a period of dairy surpluses, the government bought millions of pounds of cheese to prop up prices for struggling farmers.

To avoid letting it rot, the Reagan administration began distributing five-pound blocks of cheese to low-income families, seniors, and schools. For many who grew up in that era, that pale orange processed cheese was a lifesaver.