1

C-3PO ( Star Wars , 1977)

Few film robots are as easy to recognize as C-3PO. Introduced in Star Wars: A New Hope in 1977, this tall, golden droid was designed to handle translation and communication. Voiced in an unmistakable British accent by Anthony Daniels, his smooth metal surface, rigid stance, and gentle manner make his role in the story immediately clear. C-3PO appears in nearly every main installment of the franchise, and he was even made into toys and theme park attractions.

2

R2-D2 ( Star Wars , 1977)

Not all iconic robots speak in words. C-3PO’s companion R2-D2, first seen in Star Wars: A New Hope (1977), communicates through "beeps and whistles" rather than spoken language. He is a droid designed to assist with navigation, maintenance, and technical repairs. Within the story, he frequently carries information, fixes equipment, or helps characters escape danger. His "trashcan" shape is a masterclass in functional design, and his bravery as a "swiss-army-knife" repair droid made him arguably the most heroic character in the franchise.

3

T-800 ( The Terminator , 1984)

Is it human, or only pretending to be? When The Terminator was released in 1984, the T-800, played by Arnold Schwarzenegger in his breakout role, stood apart from earlier robots by appearing human. In fact, he’s more of a cyborg, since it combines an internal metal structure with external living tissue. Thanks to his appearance, he can move unnoticed among people, which is essential to his role in the story. Lines like "I'll be back" and "Hasta la vista, baby" are embedded in pop culture, making the T-800 one of the most iconic in cinema history.

4

Robby the Robot ( Forbidden Planet , 1956)

In 1956, long before sleek digital effects, Robby the Robot arrived on screen. His bulky metal body, exposed wiring, and clear dome head first appeared in the film Forbidden Planet . Robby can speak in full sentences, follow complex instructions, and perform tasks such as cooking, transporting people, and providing protection. After the film’s release, a similar aesthetic appeared in several television shows and movies. He was the first on-screen robot to have both a lovable personality and a complex design.

5

EVE ( WALL·E , 2008)

EVE’s design is iconic for its minimalism: she has no visible joints and no exposed mechanics. She first appears in Pixar’s 2008 animated film WALL·E . Her name means Extraterrestrial Vegetation Evaluator, and she has a limited vocabulary. Her smooth white exterior, compact shape, and floating movement make her very different from her older, more mechanical-looking predecessors. Despite her coldness, she eventually learns the warm emotions of love.

6

Dot Matrix ( Spaceballs , 1987)

With her metallic gold body, upright posture, and humanlike mannerisms, Dot Matrix, introduced in Spaceballs (1987), was designed to resemble a "protocol droid." Yes, she is a clear parody of _Star Wars_’ C-3PO, born from the genius mind of Mel Brooks. Voiced by Joan Rivers, Dot Matrix is famous for her "Virgin Alarm" and her role as a sarcastic, overprotective governess to Princess Vespa (Daphne Zuniga) rather than a technical aid.

7

RoboCop ( RoboCop , 1987)

RoboCop, played by Peter Weller, is introduced as a law-enforcement cyborg, combining human elements with heavy metallic armor. In the story, he carries out police duties such as patrol, investigation, and public order enforcement using advanced technology. The design—a silver-visored helmet and hydraulic movements— symbolized 1980s corporate greed and the loss of individual identity to the machine.

8

Johnny 5 ( Short Circuit , 1986)

Unlike the sleek EVE from WALL·E , Johnny 5 looks like a prototype, with exposed wires and tank treads. He is a small robot built for military testing, with large camera-like eyes and movable arms. After an accident alters his programming, he begins to act independently rather than following commands. He asks questions, observes everyday objects, and interacts closely with human characters. This combination of curiosity, humor, and a non-threatening appearance helped make Johnny 5 an icon of 1980s science fiction.

9

Gort ( The Day the Earth Stood Still , 1951)

Appearing in The Day the Earth Stood Still (1951), Gort is a seamless, 8-foot-tall silver sentinel who represents the terrifying potential of nuclear-age technology. He follows instructions precisely and does not engage in conversation with humans. In the film, his purpose is to enforce rules rather than explain them, acting only when necessary. His iconic "visored" eye that fires a disintegration beam and the phrase "Klaatu barada nikto" remain his enduring legacy.

10

Rachael (Blade Runner, 1982)

At first glance, Rachael (played by Sean Young) does not appear to be a robot at all. Introduced in Blade Runner (1982), she is an android created to blend into human society, with natural speech, human behavior, and no visible mechanical parts. Unlike earlier film robots, her design relies on appearance and memory rather than metal or machinery. In the story, she believes her memories and feelings are real. This focus on memory and identity, rather than physical ability or function, is why her role is still discussed in relation to artificial intelligence and what defines a human being.

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.