1

Area 51

Image: Michael Herren

Location: Nevada

Shrouded in secrecy, this military base has become synonymous with UFOs and government cover-ups. Its official purpose was testing aircraft like the U-2 spy plane and Stealth Bomber, but its classified nature fueled decades of wild speculation, ranging from secret weapons to actual aliens working for the government.

2

Coral Castle

Image: Audric Wonkam

Location: Florida

This massive stone structure was built by a single man, Edward Leedskalnin, using enormous limestone blocks—some weighing 30 tons. According to him, no heavy machinery was ever used during the construction, and he even claimed to know the secrets of the pyramids . To this day, engineers and historians debate how he moved and placed those stones with such precision.

3

Skinwalker Ranch

Image: Jacob Padilla

Location: Utah

This 512-acre property has long been at the center of UFO sightings, cattle mutilations , and alleged portals to other dimensions. The stories were so compelling that, in the ’90s, a private research organization purchased the ranch to try and make some scientific sense of the claims, conducting extensive field studies. However, after nearly a decade of research, they found no conclusive evidence.

4

Mammoth Cave

Image: Ksenia Kudelkina

Location: Kentucky

The world’s longest known cave system has its fair share of unexplored tunnels, ghost stories, and strange air currents. More than 400 miles have been mapped , yet many passages remain uncharted. Researchers have yet to fully understand the cave’s underground ecosystem, and new chambers are still being discovered today.

5

The Marfa Lights

Image: Alexandra Vo

Location: Texas

Reported since at least the late 19th century, floating orbs of light have been seen near this small town with no consistent explanation. Night watchers continue to gather at designated viewing areas along Highway 90, hoping for a glimpse. While scientific studies suggest that distorted car headlights are the most likely cause, many remain convinced otherwise.

6

The Devil’s Kettle

Image: Andrew Ling

Location: Minnesota

This unusual waterfall splits in two—one half flows normally, while the other vanishes into a deep pothole with no known exit. Scientists poured dye, ping-pong balls, and even GPS trackers into the mysterious hole, all to see where the water ends up. While researchers eventually confirmed it rejoins the river underground, exactly how and where remained elusive for decades.

7

Cahokia Mounds

Image: pcrm Dorego

Location: Illinois

Built centuries before Columbus arrived in the Americas, the ancient city of Cahokia featured massive earthen mounds, wooden palisades, and likely formed part of complex trade networks across the continent. Despite having a population rivaling London in the 1200s, according to archaeologists, the city was mysteriously abandoned in the span of a few years. No written records explain its decline, though environmental stress, resource shortages, and internal social factors are often cited as possible causes.

8

Blythe Intaglios

Image: Alexander Schimmeck

Location: California

Similar to Peru’s Nazca Lines, these giant geoglyphs are etched into the desert floor, seemingly visible only from the sky. Created by scraping away dark rocks to reveal lighter earth beneath, the figures are believed to be between 450 and 2,000 years old, depending on the specific design. While their exact purpose remains a mystery, they are believed to have had a ceremonial function.

9

The Spooklight

Image: Ben Griffiths

Location: Missouri-Oklahoma Border

Also known as the Hornet Spooklight, this floating orb has been seen since at least the late 19th century. It appears along a rural stretch of road near the small community of Hornet, Missouri, and Quapaw, Oklahoma. While some theorize it could be caused by car lights from miles away, some sightings predate automobiles.

10

Roanoke Island

Image: Stephen Crane

Location: North Carolina

In the 1580s, an entire colony vanished overnight, leaving behind only the word "Croatoan" carved into a tree. No graves, no remains—just an eerie disappearance that sparked centuries of theories, from disease and starvation to assimilation with local tribes. Modern archaeology uncovered European artifacts at sites associated with Native groups miles away, but no definitive evidence has ever solved the mystery.

1

Statue of Liberty

Image: Pierre Blaché

Location: New York City, New York

The iconic symbol of freedom and democracy, Lady Liberty stands tall on Liberty Island in New York Harbor. A fraternal gift from France in 1886, she welcomed immigrants and visitors to the United States for over a century with her torch held high , representing enlightenment and hope.

Originally, it was a brownish copper color, but after a few years of exposure to the elements, its iconic green patina—caused by the oxidation of its copper surface—began to spread. Also, did you know that her full name is actually "La Liberté éclairant le monde" , French for "Liberty Enlightening the World"?

2

Mount Rushmore

Image: John Bakator

Location: Keystone, South Dakota

Carved into the granite face of the Black Hills, Mount Rushmore features the colossal visages of four revered American presidents: George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln.

Although the monumental sculpture was never finished due to lack of funding (the original vision of sculptor Gutzon Borglum was that each president would be depicted from head to waist), it is still one of the most enduring symbols of the nation's founding principles and leadership.

3

Lincoln Memorial

Image: Kelli Dougal

Location: Washington D.C.

Honoring the 16th President of the United States, the Lincoln Memorial stands as a tribute to Abraham Lincoln's enduring legacy and his role in preserving the Union during the Civil War. An example of neoclassical architecture, it is built in the form of a classical temple , and the massive marble statue of Lincoln seated solemnly commands reverence upon entrance.

The memorial serves as a symbolic center for civil rights and has been the site of many historic speeches , most notably Martin Luther King Jr.'s "I Have a Dream" speech in 1963.

4

Gateway Arch

Image: Chris Hardy

Location: St. Louis, Missouri

Considered by some to be the tallest human-made monument in the Western Hemisphere - and the tallest arch in the world - the Gateway Arch soars 630 feet above the Mississippi River, a tribute to America's westward expansion and the pioneering spirit of its people.

Made of stainless steel with reinforced concrete infill, the structure is built to withstand earthquakes and winds up to 150 miles per hour. Inside, the arch is hollow and contains a tram system that takes visitors to an observation deck at the top.

5

Washington Monument

Image: Andy He

Location: Washington D.C.

Dedicated to the nation's first President, George Washington, this towering obelisk stands at 555 feet, making it one of the tallest stone structures in the world - and for a brief period of time between 1884 and 1889, before the construction of the Eiffel Tower, it actually was the world's tallest structure.

Its cornerstone, a 24,500-pound marble block, was specially hollowed to hold a number of memorabilia , including items associated with the monument, George Washington, and various benevolent societies.

6

USS Arizona Memorial

Image: Kirby Yardley

Location: Pearl Harbor, Hawaii

Built over the sunken remains of the USS Arizona, this memorial pays homage to the lives lost during the attack on Pearl Harbor on December 7, 1941. Only accessible by boat, the solemn structure sits just above the sunken battleship without touching it , preserving the original wreckage intact.

To this day, drops of oil occasionally leak from the ship’s deteriorating oil tanks , forming oil slicks on the water’s surface that are often referred to as "the tears of the Arizona."

7

Crazy Horse Memorial

Image: Lauren Lopes

Location: Crazy Horse, South Dakota

A colossal endeavor still in progress, the Crazy Horse Memorial is a heartfelt tribute to the Lakota leader Crazy Horse , intended to honor the culture, tradition, and resilience of Native Americans.

When it is finally completed, it will be the largest sculpture in the world , standing at 563 feet high and 641 feet long.

8

Hoover Dam

Image: Ryan Thorpe

Location: Nevada/Arizona border

Although not technically a monument, the Hoover Dam undeniably stands as a testament to American ingenuity and resourcefulness. Completed in 1936, it was originally named Boulder Dam , but the association with President Herbert Hoover endured, leading to its eventual renaming in his honor.

Spanning the Colorado River between Nevada and Arizona, the Hoover Dam is a monumental feat of engineering and a vital source of hydroelectric power and water for the Southwest United States.

9

Bunker Hill Monument

Image: Siddharth Mallya

Location: Charlestown, Massachusetts

Standing tall on Breed's Hill in Charlestown, Massachusetts, the Bunker Hill Monument commemorates the Battle of Bunker Hill , one of the early clashes in the American Revolutionary War.

Constructed between 1825 and 1843, the granite obelisk rises 221 feet and is accompanied by a statue of Col. William Prescott , a celebrated commander and hero of the Revolutionary War. Prior to the construction of the Washington Monument, it was the nation's largest-scale memorial.

10

Golden Gate Bridge

Image: Leo_Visions

Location: San Francisco, California

Spanning the Golden Gate Strait and connecting San Francisco to Marin County, the Golden Gate Bridge is an enduring symbol of American engineering and inventiveness. Opened in 1937, the iconic suspension bridge stretches 1.7 miles, and the main cables that support the weight of the roadway are made out of over 80,000 miles of galvanized steel wire.

Its distinctive orange hue, known as International Orange , was carefully chosen by consulting architect Irving Morrow to both complement the natural surroundings and enhance visibility in the frequent foggy conditions of the bay.

1

ALF

Image: Erik Mclean

In case you didn’t know, this beloved TV character’s name is not short for "Alfred." It actually comes from the term " A lien L ife F orm," but don’t be alarmed: This alien is as friendly as they come. ALF is the quirky and lovable adopted family member of the Tanner family, who gained the heart of the American public in the 80s and 90s.

ALF’s story begins after this alien’s spaceship crash-landed in the garage of the Tanner’s, a typical suburban American family. Although his many antics often bring trouble for the entire family, ALF’s big heart quickly makes the Tanners fall in love with him, harboring and keeping him hidden from the U.S. government.

2

E.T.

Image: Rick L

Are we in the presence of the most famous film alien in history? While we might not be able to answer this question (the remaining entries on this list might very well be as beloved), E.T. is definitively a heavy contender for this highly-coveted title. It’s been over 40 years since this extraterrestrial’s only on-screen appearance, but he still remains as iconic as he ever was.

Steven Spielberg’s 1982 film tells the story of Elliot, a typical American boy who befriends a lovable alien stranded on Earth. Elliot, alongside his family and friends, helps E.T. go back home, leaving us with a few of the most memorable moments in cinematic history.

3

Mork

Image: photo by Alan Light, CC BY 2.0

Not every alien on this list has to look weird: Leave it to the amazing Robin Williams to portray one of the most beloved TV aliens in history. "Mork and Mindy" shows the adventures of Mindy McConnell, an American teenager who befriends an alien simply known as "Mork from Ork."

Not many know that this now classic TV show was an offshoot of another beloved American show, "Happy Days." Williams's only appearance in a Happy Days episode impressed producers so much that they decided to give this TV legend his first chance.

4

Marvin the Martian

Image: cogdogblog, CC BY 2.0

Marvin the Martian might be the first alien on this list to pose a threat to mankind, but don’t worry: His plans usually backfire in a spectacular fashion, usually thanks to a wisecracking rabbit or to a lisping duck with anger issues.

Originally voiced by the legendary Mel Blanc, perhaps what’s more memorable about Marvin is his unusual design: You wouldn’t expect a creature of outer space to sport a red unitard, green skirt, nor a fashionable broom on his helmet, right?

5

Chewbacca

Image: Kadyn Pierce

If you had to describe Chewbacca to someone who had never seen the film, the image they would form in their head wouldn’t necessarily describe Han Solo’s partner in crime, right? After all, they would probably think of Chewie as some sort of huge and extremely adorable teddy bear, unaware of the danger they would be in if they called this iconic Wookie cute.

However, as ferocious as Chewbacca was to any Storm Trooper that dared to step in his way, he was also an extremely loyal and loving comrade to any of his many rebel friends. Few movie sounds are as memorable as Chewie’s deafening roar.

6

Xenomorph

Image: Hossam el-Hamalawy, CC BY 2.0

First things first: In case you didn’t know, the titular alien species in the " Alien " film series does have a name. Well, sort of. These jet-black monstrosities are actually known as the Xenomorph . However, should you ask an etymology aficionado about what this Ancient Greek word actually means, the answer would simply be "an alien or strange creature." So, in a way, these creatures can simply be called "Aliens.".

In any case, few extraterrestrials have instilled so much fear into the hearts of moviegoers: Their razor-sharp claws, amazing strength, and acidic blood definitively make them one of the most dangerous creatures in film history. In fact, only one fictional alien species has been able to stand their ground against the vicious Xenomorphs and, as luck would have it, they are the next entry on this list!

7

Predator

Image: Anderson Mancini from Sao Paulo, Brazil, CC BY 2.0

Way before the 2001 movie "Alien vs Predator" pitted these two science-fiction juggernauts against one another, the Predator had already established itself as the deadliest hunter in the galaxy. This alien race lives for one thing and one thing only: To prove their skills by tracking and hunting down the most dangerous and exquisite creatures.

The 1987 film "Predator" introduced the world to this cold-blooded hunter by placing him in a terrifying environment: The film follows Vietnam War veteran Major Dutch (played by Arnold Arnold Schwarzenegger) and his efforts to escape the Predator that’s hunting them in the deep jungle. However, the second Predator film saw an even more unnerving scenario: The Predator hunting down prey in the streets of Los Angeles.

8

Mr. Spock

Image: Wonderlane

Is Mr. Spock on this list? It seems only logical. In a list almost entirely comprised of extraordinary and bizarre creatures, it only took a set of pointy ears to turn actor Leonard Nimoy into one of the most instantly recognizable fictional aliens in history.

Mr. Spock has been a staple of the Star Trek universe since the very first episode of the original show aired in the 1960s. Spock quickly became a fan favorite: His highly logical brain, combat skills and passion for science made him extremely interesting to TV audiences. Not only that, Nimoy’s deep voice and magnetic personality added to the depth of this character.

9

Mars Attacks!

Image: Derpy CG

When audiences saw Tim Burton’s 1996 black comedy "Mars Attack!," they were quickly enthralled by the menacing yet funny-looking Martians attacking our country. However, few of them knew that these aliens were actually much older, dating back to a 1960s trading card game produced by Topps.

The lore established by the trading card series and the film is pretty much the same: One day, our planet finds itself invaded by a race of Martians hell-bent on taking over our planet. While the Earth is first unable to defend against their superior technology, our tenacity and grit allow us to battle these hideous space invaders.

10

Superman

Image: Esteban López

We’ll end this article with the last son of Krypton. Sometimes we tend to forget that Superman , a superhero believed by many to be the ultimate American icon, arrived on our planet as a baby from outer space. After his home planet was doomed, Kal-El’s biological father sent him far away across the galaxy, with his small vessel crash-landing into a small farm in Smallville, Kansas.

Baby Kal-El was found by Jonathan and Martha Kent, two farmers who instantly adopted him as their own child. Now known as Clark, the boy that would eventually become the "Man of Steel" found his powers at an early age, and set out to defend our world from all sorts of dangers.