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

Rebuilt from the ashes

When the British set fire to the White House in 1814, it didn’t just singe a few curtains; it gutted the place. Enter James Hoban, the original architect, who was brought back to restore what had been lost. It was a second chance for the home he first designed, and he saw it through with grit and style.

2

Madison moved out and never came back

You might have worried about the house. But what about the people inside? Well, after the fire, President James Madison packed up and never returned to the rebuilt White House. By the time it was ready again, he was on his way out of office. The next tenant, James Monroe, received the keys to the newly renovated executive mansion.

3

Once the biggest house in America

Believe it or not, the White House was once the largest home in the entire country. That might sound quaint now, we know, but back in the early 1800s, a residence with 132 rooms was as grand as it got. It’s safe to say the neighbors were impressed.

4

This place is no modest cottage

In case you’re wondering just how big the White House really is, it stretches roughly 168 feet long and 85 feet wide. On the south side, it rises 70 feet tall; on the north, 60 feet and change. A serious house for serious business.

5

It sits on a whole lot of lawn

The next time you're mowing the yard and feeling proud of your quarter acre, consider this: the White House grounds cover a whopping 18 acres. That’s plenty of room for garden parties, Easter egg rolls, and even the occasional helicopter landing.

6

Truman’s big job

By the late 1940s, the White House was falling apart—you know, creaking floors, sagging beams, and some serious plumbing problems. President Harry S. Truman had the entire interior ripped out and rebuilt. The exterior stayed the same, but inside? It was practically a brand-new house hidden behind historic walls.

7

There’s a bunker down below

Tucked underneath the East Wing is the Presidential Emergency Operations Center, or PEOC. Built during WWII, it's the secure location presidents go to in times of crisis. It’s strictly off-limits to the public—and no, it’s not a James Bond villain lair, but it’s movie-worthy for sure!

8

There’s a secret Oval Office exit

Behind what looks like just another panel in the Oval Office, there is a secret door that leads to a private hallway. President Franklin D. Roosevelt used this discreet passage to come and go without fanfare. We don’t know about you, but oh, the money we would pay to take a look at it!

9

Lincoln’s ghost still makes the rounds

You may not believe in ghosts, but plenty of people (including presidents and White House staff) have said they’ve seen or felt Abraham Lincoln’s presence in the White House. His old bedroom seems to be the hot spot. Some say he’s still keeping an eye on the place.

10

A hidden treasure trove of gifts

Foreign leaders bring all sorts of gifts when they visit the White House—from art and artifacts to, back in the day, even exotic animals. Many of these items end up tucked away inside the residence, far from public view. It’s like a museum without the tour guide.

1

Approval voting

Image: Element5 Digital

The approval voting system is an electoral mechanism in which each voter may select any number of candidates, and the winner is the candidate approved by the largest number of voters .

This differs from plurality voting, in which a voter may choose only one option from several, and the option with the most votes wins.

2

Ballot fatigue

Image: Phil Hearing

If you have ever looked at a ballot and felt overwhelmed by the long list of races and issues further down, you have experienced ballot fatigue . This occurs when voters choose not to vote on lower-ballot races or issues.

3

Blanket primary

Image: Mick Haupt

A blanket primary is an election in which voters can select candidates from any party , regardless of their own or the candidates' political affiliation. This contrasts with a closed primary, where only registered party members can vote

4

Canvass

Image: Ernie Journeys

This term has two possible meanings. On the one hand, canvassing refers to the process of aggregating and verifying all valid ballots cast , which includes absentee, early voting, Election Day, provisional, challenged, military, and overseas citizens.

The second definition of this word, in the context of elections, canvassing also refers to the act of soliciting votes .

5

Caucus

Image: Arnaud Jaegers

A caucus can refer to a closed meeting of members of the same political party or faction, typically held to select candidates or decide on policy. It can also mean a group of people united to promote a shared cause . Similar, perhaps, but not the same.

6

Electoral college

Image: Joshua Woroniecki

An electoral college is a body of people known as presidential electors , formed every four years to represent U.S. states, who formally cast votes for the election of the president and vice president .

7

Mixed ticket

Image: Tiffany Tertipes

A concept somewhat similar to the previously mentioned blanket primary, a mixed ticket is a ballot where voters may select candidates of their choice regardless of party affiliation up to the maximum allowed for each race.

8

Dark money

Image: Mathieu Turle

In the context of elections, dark money refers to funds that are donated to a political candidate during an election campaign from organizations that are not required to disclose their donor’s identities . As expected, this money is often used to influence elections.

9

Gerrymandering

Image: Element5 Digital

This unusual word describes the process of manipulating electoral district boundaries to favor one party or candidate over another. Wayne Dawkins, a professor at Morgan State University, explains it as "politicians picking their voters instead of voters picking their politicians."

10

Super PAC

Image: Mockup Free

A Super PAC (Political Action Committee) does not contribute to candidates or parties but makes independent expenditures in federal races , such as running ads, sending mail, or communicating other messages that specifically advocate for the election or defeat of a particular candidate.

11

Air gap

Image: Andrew Neel

Put in simple terms, an air gap is a physical separation between systems that requires data to be transferred manually, using methods like a disc, flash drive, or other portable media.

Election systems use air gaps intentionally to prevent or control access . The election system cannot be connected to the internet at any time.

12

Undervote

Image: Glen Carrie

As the name suggests, an undervote occurs when a voter selects fewer choices than allowed in a contest . Similarly, an overvote happens when a voter selects more choices than permitted.