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

There's an unexplained billion-year gap

Look closely at the canyon walls, and you'll notice something strange: a clean, sharp line where ancient rock simply stops, and a much younger layer begins directly above it.

This geological puzzle is called the "Great Unconformity," and it represents over a billion years of rock layers that are simply absent , as though that stretch of time never happened. In some spots, rock dated 1.8 billion years old sits directly beneath rock that is only 520 million years old. Where did the missing billion years go?

The leading theory involves the violent breakup of an ancient supercontinent, but scientists are still piecing it together.

2

During the Cold War, it hid a nuclear fallout shelter

During the Cuban Missile Crisis in 1962, the U.S. government converted part of the Grand Canyon Caverns into a fallout shelter. This dry cave system, more than 200 feet underground, was stocked with enough food and water to sustain 2,000 people. Naturally, it was never occupied, and the supplies were never used.

The caverns have since been transformed into a tourist attraction, with organized tours winding through the same underground chambers that were once intended as a refuge from nuclear war. You can even book a night's stay there.

3

The Federal Aviation Administration was founded after a crash over the canyon

In 1956, two commercial passenger planes collided in midair over the eastern Grand Canyon, killing all 128 people on board both crafts. Rescue teams struggled to reach the wreckage deep inside the canyon, and the extreme heat of the crash had caused the planes' aluminum to fuse with the bedrock. There were no survivors.

The disaster exposed a terrifying truth: the U.S. air traffic control system was dangerously outdated, relying on pilots' visual estimates and rough guesswork from controllers , with no way to separate fast-moving aircraft from slow ones, or instrument-flying planes from those navigating by sight. Congress responded by passing legislation that created both the Federal Aviation Administration (FAA) and the National Transportation Safety Board.

4

A hoax suggested that an Egyptian civilization had lived there

In 1909, the Arizona Gazette reported that an explorer named G. E. Kinkaid had discovered a vast underground citadel inside the canyon, filled with artifacts linked to ancient Egyptian civilization. He even claimed the expedition had been funded by the Smithsonian.

This story described hieroglyphics on the walls, mummies in the chambers, and relics pointing to a direct connection with the Egypt of the pharaohs. It was incredibly detailed, and it was, of course, a hoax. No evidence for any of Kinkaid's claims ever surfaced.

5

Fewer than 100 people have ever hiked its full length

Among the few people who have completed the through-hike of the Grand Canyon is Jen Hogan, the first woman to accomplish it, finishing her journey in 2021–2022.

It’s a full 800-mile length below the rim. The route involves extreme heat, flash floods, near-impassable areas, and stretches with no water or trail whatsoever. Around 60 or 70 people have reportedly accomplished it. This makes it one of the most exclusive feats on Earth.

6

The Grand Canyon's rocks predate dinosaurs entirely

Visitors scanning the canyon walls for fossils are often surprised to learn they won't find any dinosaur bones here. The rock layers of the Grand Canyon are simply older than dinosaurs. This fact alone can be shocking: staring at its walls means staring at marine fossils from as far back as 1.2 billion years ago. Some of its caves hold the remains of ancient mammals. The canyon is a window into a world that existed long before the dinosaurs, when the land that is now Arizona lay beneath a shallow sea.

7

The park is bigger than Rhode Island

Numbers alone rarely capture the Grand Canyon's scale, so here's a different approach. Rhode Island covers about 1,214 square miles, and the Grand Canyon National Park spans 1,904 square miles.

The canyon's depth exceeds four Empire State Buildings (which is 1,454 feet) stacked on top of one another. That’s 6,093 feet at its deepest point.

8

But it's not the deepest canyon on Earth

For all its grandeur, the Grand Canyon does not hold the depth record. Pictured above, the Yarlung Tsangpo Grand Canyon in Tibet, China, plunges to 17,567 feet, which is nearly three times deeper. Carved by the Yarlung Tsangpo River as it cuts through the eastern Himalayas, that canyon is so remote and extreme that it remained largely uncharted until the late 20th century.

9

It is home to a pink rattlesnake found nowhere else on Earth

The Grand Canyon Pink Rattlesnake has a pinkish-red coloring that matches the canyon's own distinctive rock walls so closely that it's nearly invisible. It is found nowhere else in the world. Officially classified as Crotalus oreganus abyssus , it has darker diamond-shaped markings along its back that deepen the camouflage further.

10

There's a village at the bottom: Supai Village

For over 1,000 years, the remote village of Supai has been home to the Havasupai Tribe, the People of the Blue-Green Waters. It is located an eight-mile hike from the rim, but sits roughly 3,000 feet deep inside the Grand Canyon.

The U.S. Department of Agriculture has called it the most remote community in the contiguous United States, and it has no automobiles and no road access. The only ways in are on foot, by mule, or by helicopter. It is also the only place in the United States where the postal service still delivers mail by mule train.

1

George Wilson (1830): The man who refused his own pardon

In 1829, George Wilson and his accomplice James Porter robbed a U.S. mail carrier in Pennsylvania. Both were convicted in May 1830 on six counts, including putting the carrier's life in jeopardy, and sentenced to hang within weeks.

Porter was executed on schedule. But Wilson's influential friends petitioned President Andrew Jackson, who granted Wilson a formal pardon in June 1830, saving him from the gallows. Then Wilson did something that had never happened before in American history: he refused it.

The case was so unprecedented that it reached the Supreme Court in 1833, housed at the Capitol in Washington, D.C., as illustrated above. Chief Justice John Marshall ruled that the pardon couldn’t be valid without acceptance. However, Wilson was never executed. He served his prison sentence and was eventually pardoned a second time by President Martin Van Buren in 1841.

2

Richard Nixon (1974): The only president ever pardoned

On the night of June 17, 1972, five operatives were arrested breaking into the Democratic National Committee offices at the Watergate complex in Washington, D.C. Investigations revealed that President Richard Nixon had known about the cover-up and actively participated in it. Facing near-certain impeachment, Nixon became the only U.S. president ever to resign from office, stepping down in 1974.

Just 30 days later, his successor Gerald Ford announced from the Oval Office that he was granting Nixon "a full, free, and absolute pardon" for all offenses against the United States committed between 1969 and 1974. No charges had even been filed. The decision was widely condemned. Many historians believe it cost Ford the 1976 presidential election to Jimmy Carter. Nixon accepted the pardon but never admitted criminal guilt, expressing only "regret" for how he had handled the situation.

3

Iva Toguri D'Aquino (1977): The woman they called "Tokyo Rose"

Iva Toguri D'Aquino was a Los Angeles-born 25-year-old visiting a sick relative in Japan when the attack on Pearl Harbor stranded her there in December 1941. The Japanese government declared her an enemy alien and coerced her into broadcasting on Radio Tokyo's Zero Hour program.

This was a Japanese psychological warfare strategy that utilized English-speaking women, eventually all referred to collectively as " Tokyo Rose," to broadcast demoralizing messages intended to weaken Allied troop morale. After Japan's surrender, journalists identified Toguri as one of the voices.

A jury convicted her of treason in 1949, and she was sentenced to 10 years in prison. She served six years. After a 1976 CBS 60 Minutes segment revealed key witnesses had lied, President Gerald Ford granted her a full and unconditional pardon in 1977, on his final day in office. It remains the only presidential pardon ever granted for a treason conviction in U.S. history.

4

Jack Johnson (2018): A champion pardoned 72 years after his death

John Arthur "Jack" Johnson was the first Black man ever to hold the world heavyweight boxing championship. In May 1913, a jury convicted him under the Mann Act (a federal law against transporting women across state lines for "immoral purposes") for traveling with his white girlfriend, whom he had since married.

Johnson skipped bail, fled to Canada, and fought two world title defenses in Paris before losing the belt in Havana in 1915. He surrendered to U.S. authorities in 1920 and served nearly a year in Kansas. He died in a car crash at age 68 in North Carolina in 1946.

After years of bipartisan lobbying and a call from actor Sylvester Stallone, President Trump signed Johnson's posthumous pardon in the Oval Office in 2018, 105 years after the conviction.

5

Samuel Mudd (1869): The doctor who set the assassin's leg

Hours after John Wilkes Booth shot President Abraham Lincoln at Ford's Theatre in Washington, D.C., one April night in 1865, Booth arrived at the Maryland farm of Dr. Samuel Mudd with a broken leg.

Mudd set the fracture and gave Booth shelter. When investigators linked Mudd to Booth, including through prior meetings in 1864, he was tried by a military commission and convicted of conspiracy. Sentenced to life imprisonment with hard labor, he was sent to Fort Jefferson, a remote military prison on an island 70 miles west of Key West, Florida.

In 1867, a deadly yellow fever outbreak killed the prison's doctor. Mudd stepped in, treating patients and helping contain the epidemic. A petition signed by 299 enlisted men and officers was sent to President Andrew Johnson praising Mudd's courage. Johnson granted Mudd a full and unconditional pardon in 1869. Mudd was released on March 8 and returned to his Maryland farm. His conviction was never overturned; the pardon freed him, but the guilty verdict stood.

6

Marc Rich (2001): A fugitive pardoned on the last day

Marc Rich was a billionaire commodities trader indicted in 1983 on 65 counts, including tax evasion, wire fraud, and trading oil with Iran during the 1979–1981 hostage crisis. Before facing trial, Rich fled to Switzerland, where he remained a fugitive from U.S. justice for 17 years.

On January 20, 2001, his very last day in office, President Bill Clinton granted Rich a full pardon, bypassing the standard Justice Department review process. T he pardon ignited one of the biggest controversies of Clinton's presidency. Rich's ex-wife Denise had donated more than $1 million to Democratic causes and the Clinton Presidential Library.

A federal investigation led by prosecutor Mary Jo White was launched but ultimately found no criminal wrongdoing by Clinton. Clinton's own Justice Department had recommended against the pardon. Rich died in Switzerland in June 2013 at the age of 78, never having returned to the United States.

7

Patty Hearst (2001): From kidnapped heiress to bank robber

Patricia Hearst, the 19-year-old granddaughter of newspaper magnate William Randolph Hearst, was kidnapped from her apartment in Berkeley, California, in 1974. She was taken by a radical militant group called the Symbionese Liberation Army.

After weeks in captivity, in which she was kept in a closet, blindfolded, she appeared in a bank surveillance video holding a rifle and participating in the robbery of a bank in San Francisco. She was captured in September 1975. Her defense argued she had been brainwashed and acted under duress. A jury rejected that argument, and she was convicted of bank robbery in 1976 and sentenced to 7 years.

President Jimmy Carter commuted her sentence in 1979 after she had served approximately 22 months. She was released and married her former bodyguard. In January 2001, President Bill Clinton granted her a full pardon in the final hours of his presidency.

8

Vietnam Draft Evaders (1977): The biggest blanket pardon in U.S. history

On his first full day as president in 1977, Jimmy Carter signed Proclamation 4483, granting an unconditional pardon to all Americans who had violated the Military Selective Service Act in the span of U.S. involvement in Vietnam.

The government estimated that approximately 210,000 men had been formally accused of draft violations , while hundreds of thousands more had never been charged. Many had fled to other countries, roughly 90% to Canada, where they had been welcomed as legal immigrants.

Carter had campaigned openly on the promise, calling it necessary to heal a nation still divided by the war. The pardon did not extend to military deserters. Veterans' organizations were furious. Despite the backlash, an estimated 50,000 of those eligible chose to remain in Canada permanently, never returning home.

9

Scooter Libby (2007 / 2018): The spy scandal at the heart of the White House

Lewis "Scooter" Libby served as Chief of Staff to Vice President Dick Cheney during the George W. Bush administration. In 2003, the identity of Valerie Plame (a covert CIA officer) was leaked to journalists, apparently in retaliation against her husband, former Ambassador Joseph Wilson, who had publicly challenged the administration's case for the Iraq War.

Though Libby was not charged with the leak itself, he was convicted in 2007 of four felony counts: obstruction of justice, two counts of perjury, and making false statements to the FBI. He was sentenced to 30 months in prison and fined $250,000. Later that same year, President Bush commuted Libby's prison sentence, calling it "excessive," but left the conviction, fine, and probation intact; he declined to grant a full pardon. Eleven years later, in 2018, President Donald Trump issued a full pardon, completely wiping Libby's record clean.

10

Roger Clinton (2001): The president's half-brother

Roger Clinton is the younger half-brother of President Bill Clinton. Roger was given the Secret Service code name "Headache" during his brother's administration. In 1984, Arkansas state police ran an undercover sting operation that caught Roger selling illegal drugs to an informant. He pleaded guilty in 1985 to charges of conspiracy to distribute drugs and served approximately one year in federal prison, completing his sentence in 1986.

14 years later, on his last day in office, President Clinton granted Roger a full pardon, clearing his criminal record. The pardon drew relatively little public outrage compared to the Marc Rich case.