1

Dundas Castle, Roscoe, New York

Image: Annie Spratt

Also known as Craig-e-Clair, this castle was built by Ralph Dundas in the early 20th century. It is an architectural marvel of stone and copper.

Dundas died before the castle was completed, and his wife was reportedly committed to a sanitarium shortly after. Consequently, no member of the Dundas family ever actually lived in the mansion. This has led to the "Ghost of Dundas Castle" legends, with locals claiming to see a woman in white wandering the unfinished halls, waiting for a housewarming party that never happened.

2

Rockwell House, Milledgeville, Georgia

Image: Clem Geiss

Built in 1838, the Rockwell House is a stunning example of Federal-style architecture, but its beauty is shadowed by a dark past. It was originally built for Colonel Samuel Rockwell, a prominent lawyer.

Local lore whispers about the "Rockwell Ghost," believed to be a young girl who died during a yellow fever outbreak. However, the house’s most tangible secret lies in its survival; it has endured multiple fires and periods of extreme neglect. In recent years, it has become a focal point for preservationists who uncovered hidden structural reinforcements that suggest the house was built to be an impenetrable fortress of its era.

3

Elda Castle, Ossining, New York

Image: Nitrogel

If the name David Abercrombie sounds familiar, it’s because he co-founded the clothing company Abercrombie & Fitch . But in the 1920s, he also built this granite castle, named Elda (an acronym of his children’s names), as a secluded retreat.

The castle features a network of spiral staircases and open-air porches designed to blend the indoors with the rugged wild. Its abandonment, however, is a sheer tragedy. After the family moved out, the castle was used as a research facility and later fell victim to vandals. Legend has it that a fire in the 1940s was started by squatters, leaving behind a charred stone husk that resembles a medieval ruin more than a 20th-century home.

4

Mongo's Castle, Memphis, Tennessee

Image: Denny Müller

A stark contrast to the classical mansions of the South, Mongo’s Castle was the passion project of Mongo Bebe, a man who built his home out of scrap stone, Ashlar blocks, and found materials.

The house is a maze of folk-art eccentricity. The builder intended it to be a community center and a symbol of African-American heritage and self-reliance. It stands today as a decaying puzzle, with many neighbors still unsure of the structural logic behind its towering, uneven walls.

5

Bannerman's Castle, Pollepel Island, New York

Image: Leonard G., Public domain, via Wikimedia Commons

Rising from the Hudson River, this castle was never intended to be a home; it was a giant advertisement and warehouse for Francis Bannerman VI’s military surplus empire.

In 1920, 200 tons of gunpowder and shells exploded in the castle’s powder house, blowing out a significant portion of the walls. The ground is still considered unstable due to the remnants of military munitions, and the inscriptions on the walls are actually warnings and advertisements for the Bannerman business. Do you dare visit this mansion?

6

Castle Mont Rouge, Rougemont, North Carolina

Image: Florian Delée

This whimsical, onion-domed castle looks like it belongs in the Russian countryside rather than the North Carolina woods. It was designed by sculptor Robert Mihaly, but he ended up abandoning the project in the early 2000s following a personal tragedy and financial hurdles.

The castle remains an "empty sculpture," filled with intricate marble work and unfinished turrets. The bizarre architectural fusion lacks a standard floor plan, making it nearly impossible to convert into a functional residence without destroying its artistic integrity.

7

Ha Ha Tonka Castle, Camdenton, Missouri

Image: Hannah McBride

Robert Snyder, a wealthy Kansas City businessman, began building this European-style castle in 1905. He wanted a retreat that overlooked the breathtaking Ha Ha Tonka Spring.

Yet, Snyder never got to see his dream finished; he was killed in one of Missouri’s first recorded automobile accidents just a year after construction began. His sons finished the castle, but it was gutted by a fire in 1942. There’s a hidden network of caves beneath the castle, which were rumored to be used by outlaws and later as a natural "refrigerator" for the estate’s kitchen.

8

Carleton Island Villa, Cape Vincent, New York

Image: Tama66

This once-magnificent villa was built for William Wyckoff, who made a fortune with the Remington Typewriter Company.

The Secret: Wyckoff’s dream turned into a nightmare on the very first night he stayed in the house. He suffered a massive heart attack and died in his sleep. His wife had passed away a month prior, leaving the villa to a son who had no interest in it. The house has stood empty for over 70 years, its secret being the tragic "cursed" timing that prevented it from ever functioning as a family home.

9

Dicksonia Plantation, Lowndesboro, Alabama

Image: Theo Bickel

Dicksonia was a quintessential antebellum mansion, featuring the massive columns and wrap-around porches synonymous with the Old South.

Unlike many plantations that were destroyed during the Civil War, Dicksonia survived the conflict only to be destroyed by a mysterious fire in 1939. Its "ghost pillars," however, remained standing long after the wooden house burned away. These towering brick columns became a haunting landmark , representing the structural skeletons of a forgotten social order.

10

Wyndcliffe, Rhinebeck, New York

Image: Peter Herrmann

This house is the literal origin of the phrase "Keeping up with the Joneses." Though often referred to as a "Mystery Mansion" by urban explorers, this is the ruin of Wyndcliffe, the estate of Elizabeth Schermerhorn Jones.

Elizabeth’s mansion was so grand and intimidating that it prompted her neighbors—including the Astors—to build even larger homes to compete. The secret of Wyndcliffe is the psychological impact of its architecture; it was built to inspire envy, and its current state of absolute decay is a poetic commentary on the fleeting nature of social status.

1

What are bills made of?

Unlike other currencies, dollar bills are not made of paper or plastic. U.S. dollar bills are made from a special fabric blend composed of 75% cotton and 25% linen. This mix makes the bills extremely durable and resistant, and they can be folded about 4000 times before tearing.

2

What bills are valid?

Any U.S. dollar bill that was legally printed is valid, no matter how old, as American currency does not have an expiration date. While some bills might not be accepted by businesses of foreign exchange services due to their condition or if they are a discontinued version of the bill, the bills themselves are still valid, and American banks will accept them, though they might take them out of circulation.

3

American leaders

Five bills have a depiction of an American president. The exceptions are the $10 bill, with Alexander Hamilton on the front, and the $100 bill, with Benjamin Franklin. The $1 bill, depicting George Washington, is extremely symbolic: several elements are repeated 13 times as a nod to the thirteen colonies, and it showcases the Bald Eagle and the Eye of Providence as a sign of God watching over America.

4

A change in size

Did you know that dollar bills used to be so big that they were nicknamed "horse blankets"? Original dollar bills were 7.4 × 3.1 inches. In 1929, the Treasury Department reduced the size of bills to 6.14 × 2.61 inches to reduce production costs and materials. Old bills, though still valid, are worth much more as collector items.

5

Uniformity

Besides their value and design, all dollar bills have the same size (6.14 × 2.61 inches), color, and weight (1 gram) , which sets American currency apart from other countries where bills of different values are differentiated by size, color, or both. Why doesn’t the U.S. implement differences among bills? The cost of adapting vending machines, bank drawers, and ATMs to new bill sizes would cost billions of dollars.

6

Hard to copy

Originally, dollars were not green, but black. As time passed, green ink was favored, as it was cheap and did not fade as much as black. The new color also prevented people from using black-and-white cameras to create counterfeit money. Currently, dollar bills are predominantly green, but newer versions also include extra colors, such as pink, orange, or purple.

7

A $100,000 bill?

Have you ever seen a $500 or 1,000 dollar bill? What about a $100,000? Up until 1945, the U.S. Treasury printed $500, $1,000, $5,000, $10,000, and $100,000 notes , in addition to the values currently in use. These higher-value notes were mainly intended for bank and government use, but were sought by criminals as they made it easier to hide large amounts of money. Even though they were officially discontinued in 1969, these notes are still valid, though rare, and they have a high worth as collector's items.

8

No numbers

Unlike bills, American coins have different sizes and colors related to their value. Originally, gold, silver, and copper were used for coins, but modern coins are made of copper, zinc, or nickel. Besides their size and design, the value of each coin is printed in letters, not in numbers , alongside depictions of American presidents.

9

Liberty for all (the coins)

By law, all American coins must include six specific details : the word ‘Liberty’, the name of our country, the national motto "In God We Trust", the oldest American motto "E Pluribus Unum", the value of the coin, and the year. Each coin also includes a mint mark that shows where it was made: "P" for Philadelphia, "D" for Denver, "S" for San Francisco, and "W" for West Point.

10

A global currency

The American dollar is one of the most powerful currencies in the world, acting as a backbone for international trade and finances. It is estimated that two-thirds of the physical dollars in circulation are outside American territory. Besides the U.S. and its territories, eight sovereign nations have the U.S. dollar as their official currency, with several more accepting it as legal tender.

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.