1

Mississippi River

Image: Justin Wilkens

Beloved by blues musicians and immortalized by Mark Twain, the Mississippi has been central to exploration, trade, and American identity. The name comes from the Ojibwe/Anishinaabe word misi‑ziibi, meaning "Great River" or "Father of Waters."

Flowing some 2,320 miles, its watershed drains roughly 41% of the continental U.S., and its vast system remains critical for both commerce and agriculture.

2

Missouri River

Image: Jayden Herr

The name of the Missouri River comes from the Algonquian term ouemessourita, meaning "people with dugout canoes."

A crucial highway for early explorers like Lewis and Clark, as well as later settlers, this 2,300-mile-long river was once home to Native tribes such as the Missouria. Today, it remains a vital part of regional agriculture and river transport.

3

Hudson River

Image: Harry Gillen

Originally called Muh-he-kun-ne-tuk ("waters that are never still") by the Mohicans, the river was later renamed after Henry Hudson, who explored it in 1609 for the Dutch East India Company.

The Hudson Valley later grew into both an economic and cultural hub, inspiring the Hudson River School of painters and playing a strategic role during the American Revolution.

4

Colorado River

Image: Mike Newbry

The name Colorado comes from Spanish, meaning "reddish," a reference to the red silt once carried by the river. Before 1921, its upper course was known as the Grand River, until Congress renamed it to reflect the state of Colorado.

Over millions of years, the Colorado River carved the Grand Canyon, one of the world’s most dramatic natural landscapes. Today, it supports irrigation across seven U.S. states and northern Mexico and generates hydroelectric power through major dams such as Hoover Dam and Glen Canyon Dam.

5

Rio Grande

Image: Sara Cottle

The name Rio Grande means "Big River" in Spanish. Serving as the border between the U.S. (Texas) and Mexico, it has defined geopolitical boundaries since the end of the Mexican-American War in 1848.

Historically, the Rio Grande supported Indigenous communities such as the Pueblo and Apache peoples, and later Spanish missions and settlements. Today, it serves as a lifeline for agriculture, cities, and wildlife habitats across the arid regions of Texas, New Mexico, and northern Mexico along its 1,896-mile course.

6

Ohio River

Image: Joshua Canter

"Ohio" comes from the Seneca word ohi:yo’ , meaning "good river" or "large creek." Formed by the confluence of the Allegheny and Monongahela Rivers at Pittsburgh, it flows for about 981 miles through six states before joining the Mississippi River.

In early America, the Ohio was a key route for westward expansion and trade. Settlements along its banks grew into important commercial and industrial centers, including cities like Cincinnati, Louisville, and Pittsburgh, and its fertile floodplains supported agriculture that fueled the growing nation.

7

Columbia River

Image: Stephen Walker

The Columbia River was named after the Columbia Rediviva , the ship captained by Robert Gray , which itself was named in honor of Christopher Columbus. For thousands of years, the river served as a vital trade network for numerous Native American tribes, and later became central to the North American fur trade.

Its fertile valleys supported settlements and agricultural development throughout the Pacific Northwest. Today, the Columbia is a major source of hydroelectric power, with major dams such as Grand Coulee and Bonneville supplying electricity to millions of people.

8

Potomac River

Image: Sara Cottle

The name "Potomac" comes from a Native Algonquian word, likely Patawomeck (probably Piscataway), meaning "river of swans." The river flows past Washington, D.C., and George Washington’s Mount Vernon estate overlooks it.

During the colonial era and the Civil War, it was a crucial transport route, and its watershed continues to hold historical, cultural, and political significance today.

9

Delaware River

Image: Clay Banks

Named after Lord De La Warr (Thomas West), an English nobleman and colonial governor, the Delaware River is best known for George Washington’s daring 1776 crossing, which surprised Hessian troops in Trenton and provided a crucial morale boost for the Continental Army during the Revolutionary War.

Over the years, the river has remained vital for trade and industry, shaping the mid-Atlantic economy and supporting major ports in New Jersey, Pennsylvania, and Delaware.

10

Susquehanna River

Image: Jennifer Wick

The name "Susquehanna" likely comes from the Lenape word siskëwahane, meaning "Muddy River" (though other translations, such as "Oyster River," have been proposed). One of the oldest river systems in North America, the Susquehanna stretches about 444 miles from New York through Pennsylvania to the Chesapeake Bay in Maryland.

It supported Indigenous communities such as the Susquehannock, and early colonial settlements relied on it for transport, fishing, and trade. Its fertile valley later powered mills, contributed to the region’s coal and lumber industries, and played a key role in shaping the development of the Mid-Atlantic.

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

The disappearance of Amelia Earhart (1937)

The first entry on our list is dedicated to a world-renowned flight pioneer, Amelia Earhart, who vanished while attempting to become the first woman to fly around the globe , leaving behind only fragments of her plane and endless speculation. Radio failure, poor visibility, and fuel issues are speculated to be contributing factors to her disappearance.

Even with modern technology and repeated searches, no one has ever found definitive proof of what happened to Amelia or her aircraft.

2

The D.B. Cooper hijacking (1971)

In 1971, Dan Cooper, a seemingly quiet man, boarded a plane in Portland, Oregon, which he promptly hijacked when the aircraft was in the air. He demanded $200,000 over the radio.

The plane landed in Seattle, where authorities met his demands. Cooper released all 36 passengers in exchange for the cash and parachutes. He then ordered the remaining crew to fly toward Mexico City at a low altitude and slow speed. Somewhere over southwest Washington, he lowered the aircraft's aft stairs and jumped into the freezing night, never to be seen again.

3

The disappearance of Jimmy Hoffa (1975)

The powerful union leader left a Detroit restaurant in 1975 and simply vanished . Witnesses last saw him standing by his car in the restaurant’s parking lot, and investigators believe he was coaxed into a car by people he recognized, thinking the meeting location had changed. He was never seen again. Searches in fields, lakes, and construction sites turned up nothing. To this day, it remains one of the most famous unsolved mysteries in American history.

Rumors range from mob connections to government cover-ups, but none have been proven. Ever since then, Hoffa’s name has become shorthand for anything that disappears without a trace.

4

The Yuba County Five (1978)

In what came to be known as "America’s Dyatlov Pass", five friends vanished after attending a basketball game in the town of Chico, California. Months later, the bodies of four members of the group were found in the mountains under mysterious conditions .

The remaining member of the original party was never located, and their strange route into deep snow remains unexplained.

5

The Sodder Children (1975)

A fire destroyed the Sodder family home in West Virginia, but five children were never found among the remains of the house. Because of physical inconsistencies at the scene and strange sightings afterward, the family always believed they survived.

Over the years, strange sightings and letters fueled hope and confusion alike, but no real evidence has ever been found. Because of these clues, the Sodders never held a funeral and instead famously erected a billboard on Route 16, offering a reward for information and keeping the case in the public eye for decades.

6

The Springfield Three (1992)

On a warm summer night in 1992, Sherrill Sherrill Levitt, her daughter Suzie, and Suzie's friend Stacy vanished from their home in Springfield, Missouri, leaving behind their cars, purses, and even the family dog .

Friends arriving the next morning found the house empty but unlocked. Despite thousands of leads, no evidence or remains have surfaced. The case remains one of the most talked-about disappearances in small-town America to this day.

7

The Gardner Museum Heist (1990)

Back in 1990, two men dressed as police officers entered Boston’s Isabella Stewart Gardner Museum and stole 13 works of art worth over $500 million .

No piece has ever been recovered. Empty frames still hang on the museum walls, a quiet tribute to one of history’s most expensive thefts.

8

The Max Headroom broadcast hijack (1987)

1980s television viewers might remember Max Headroom as a somewhat clumsy computer AI TV personality and ad spokesperson. In 1987, Chicago viewers were startled when a strange figure wearing a Max Headroom mask interrupted TV broadcasts with odd messages .

The stunt lasted only seconds, but no one was ever caught or identified. It remains one of the strangest unsolved moments in television history.

9

The Great Lakes ghost ships

Over the years, s everal ships have vanished or been found adrift on the Great Lakes , their crews gone without explanation. Cold weather, sudden storms, and superstition all play roles in the stories, but some cases defy logic. The vast inland seas are simply too big to be accessible with the current technology.

Among the most notable unsolved cases, we can mention Le Griffon, a ship that vanished during her maiden voyage in 1679, the SS Banockburn, known as the "Flying Dutchman of Lake Superior," disappeared during a storm in 1902, or the SS Chicora, a luxury steamer lost in a violent winter gale while carrying a cargo of flour, in 1895.

10

The Dulce Base Mystery

Beginning in the 1970s, a constant array of strange lights, unmarked aircraft, and talk of secret tunnels near the town of Dulce has fueled decades of conspiracy theories in this otherwise quiet area to this day.

While skeptics blame radar tests or imagination, locals still report odd sightings in the desert skies.