General General 7 min read

Sin City’s secrets

Fascinating facts about Las Vegas you won't find on travel guides

Image: Paul IJsendoorn

A man once sold every single thing he owned, flew to Las Vegas, and bet the whole lot on a single spin of the roulette wheel. Do you think he won? There are 600 miles of concrete flood tunnels under Sin City—can you estimate how many people live there? Most of the profits of the whole city come from one single game; could you guess which one it is? Read on to find all the answers to these stunning facts about Las Vegas, Nevada.

1
The man who sold everything he owned and bet it all on one spin

Image: Pavel Danilyuk

In 2004, a 32-year-old British man named Ashley Revell walked into the Plaza Hotel and Casino in Las Vegas and placed every dollar he had in the world on a single spin of the roulette wheel.

In the months before, Revell had sold his house in Kent, his BMW, his Rolex watch, his golf clubs, his electronics, his furniture, and every piece of clothing he owned. The grand total of his liquidated possessions came to $135,300 . He pushed the entire stack of chips onto red as the ball was already spinning. It landed on Red 7.

Revell walked away with $270,600, exactly double what he had come in with. He tipped the croupier $600 on the way out. The whole thing was filmed by Sky One for a reality mini-series called Double or Nothing .

2
Beneath the casinos, an estimated 1,500 people live underground

Image: Stephen Leonardi

Below the glittering hotels and neon lights of the Las Vegas Strip runs a network of concrete flood drainage tunnels stretching roughly 600 miles beneath the city. Built in the 1990s to manage flash flooding in the Nevada desert, these tunnels have become an unofficial home for hundreds of the city’s unhoused residents.

It is estimated that between 1,200 and 1,500 people live there . Some residents have constructed makeshift shelters from plywood and salvaged metal deep inside the tunnels, occasionally just yards below the casino floors above them.

The tunnels pose serious dangers: flooding risk during desert rainstorms, extreme heat, and high rates of substance abuse. A network of nonprofits, outreach teams, and government agencies coordinates aid by providing the residents with essentials and offering them long-term case management, like treatment and housing placement.

3
Las Vegas has a literal black book of people banned for life

Image: BehindTheTmuna

Since 1960, the Nevada Gaming Control Board has maintained what it officially calls the List of Excluded Persons, better known as the Black Book. The original publication was a black-covered booklet held together with Scotch tape, listing eleven people deemed to have "notorious or unsavory reputations."

Most of the early entries were organized crime figures: Chicago outfit boss Sam Giancana; enforcer Anthony "Tony the Ant" Spilotro, whose violent exploits inspired Joe Pesci’s character in the film Casino ; and nine other mob associates. Anyone whose name appears on the list is permanently banned from entering any licensed gaming establishment in the state of Nevada.

Violating the ban is a gross misdemeanor under Nevada law. As of 2026, there are 37 names on the list. No one has ever successfully appealed their removal.

4
Strange casino rules: no clocks, no windows, no soft dice

Image: Elizabeth Ferreira

Las Vegas casinos are designed to keep gamblers at the tables as long as possible. Clocks are banned to distract players from the passing of time. Windows are eliminated so that they cannot tell whether it is noon or 3 a.m.

What’s more, Nevada law governs even the dice. The Nevada Gaming Control Board requires casino dice to be perfectly transparent so that no hidden weights can be concealed inside . Each die must be precision-manufactured to within 1/10,000th of an inch, with razor-sharp corners and edges showing no rounding whatsoever. They are inspected regularly and, in high-stakes games, replaced every eight hours of play to ensure consistent rolls.

5
The famous Las Vegas Strip is not actually in Las Vegas

Image: David Lusvardi

The stretch of Las Vegas Boulevard South that the world knows as the Strip does not lie within the city limits of Las Vegas. This is the area that’s home to Caesars Palace, the Bellagio, MGM Grand, the Venetian, Mandalay Bay, and dozens of other iconic venues.

Technically, it falls within an unincorporated community called Paradise , which is governed by Clark County rather than the city of Las Vegas. Paradise was deliberately established in 1950, when casino owners moved to avoid Las Vegas city taxes and regulations while continuing to trade on the city’s name and benefit from its infrastructure.

The city of Las Vegas actually begins further north along the boulevard, near the Stratosphere. Paradise covers approximately 54 square miles and has a residential population of around 220,000 people, which means it’s one of the largest and most densely populated unincorporated communities in the United States.

6
The Luxor’s sky beam is the most powerful artificial light on earth

Image: Pavel Špindler, CC BY 3.0, via Wikimedia Commons

Rising straight up from the apex of the black pyramid-shaped Luxor Hotel and Casino, the Luxor Sky Beam has been one of the most recognizable sights in Las Vegas since the hotel opened in October 1993. It is, by any measure, the most powerful artificial light beam on the planet. The beam is produced by 39 individual xenon lamps, each with 7,000 watts and roughly the size of a washing machine, focused through computer-designed curved mirrors into a single concentrated column.

Together, they generate an estimated 42.3 billion candlepower. On a clear night, airline pilots have reported seeing the beam from as far as 250 miles away. The total operating cost, confirmed by Luxor engineer John Lichtsteiner, is $51 per hour, of which $20 is electricity. That adds up to $480 a day only for lighting the signature beam each night —or $175,200 a year.

7
Las Vegas is home to the tallest observation tower in the US

Image: Dave Morgan

Standing 1,149 feet above the Las Vegas valley, the Strat Tower, officially rebranded from the Stratosphere in 2020, is the tallest freestanding observation tower in the US and the second-tallest in the entire Western Hemisphere, surpassed only by the CN Tower in Toronto at 1,815 feet. It is also the tallest building in Nevada and the tallest structure west of the Mississippi River.

At the top, the Strat offers four outdoor thrill rides, including one that dangles riders 64 feet beyond the edge of the building on a mechanical arm, over 900 feet above the ground.

8
Slot machines account for around 60% of all casino revenue

Image: Elizabeth Ferreira

Walk into any Las Vegas casino, and the first thing that surrounds you (and the loudest) is the rows of slot machines that line nearly every available wall and corridor. That layout is not a coincidence.

It is estimated that slot machines consistently generate approximately 60 to 65 percent of all casino gaming revenue in Nevada. There is roughly one operating slot machine for every eight residents of Las Vegas. Nevada law requires that video slot machines pay out a minimum average of 75 percent, though Strip machines in practice typically return 87 to 97 percent.

Casinos place the most visible, most tempting machines near entrances, elevators, and high-foot-traffic corridors , a placement strategy that has been studied and refined over decades. Despite the rise of poker rooms and sports betting in recent years, slot machines have remained the single largest source of gaming income in Las Vegas without interruption for more than half a century.

9
The gambling capital of the world does not sell lottery tickets

Image: Obi

Nevada is one of only two states in the entire United States that have no state lottery, the other being Utah. You cannot legally walk into a convenience store and buy a $2 scratch-off ticket.

The reason is straightforward and has nothing to do with moral opposition. Nevada’s gaming industry has lobbied persistently and successfully against a state lottery since gambling was first legalized in 1931, on the grounds that a government-run lottery would directly compete with casino revenues.

10
FedEx was saved from bankruptcy by a Las Vegas blackjack table

Image: Joshua Santos

In 1971, FedEx, then called Federal Express, was days away from collapse. Founder Frederick W. Smith had built the company on the revolutionary idea of overnight package delivery using a central hub-and-spoke air network, but the business was not working.

The company had roughly $5,000 left in its operating account. It was not enough. Facing what appeared to be the end, Smith flew to Las Vegas and sat down at a blackjack table. He gambled the company’s last $5,000 and turned it into $27,000, which was just enough to cover that week’s fuel costs and keep the planes in the air. The breathing room bought by that blackjack session gave Smith enough time to secure additional financing. Today, FedEx employs more than 500,000 people worldwide and is valued at over $60 billion.

General General 4 min read

The secrets of the greenback

Dollar bills are green for this reason

Image: Pepi Stojanovski

The U.S. dollar is one of the most powerful and recognizable currencies in the world, but its physical form is unique for many other reasons . From its composition to its symbols, dollar bills and coins are carefully designed to combine history, security, and convenience. Let’s explore our national currency!

1
What are bills made of?

Image: Viacheslav Bublyk

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?

Image: U. S. Government, The Bureau of Engraving and Printing, Public domain, via Wikimedia Commons

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

Image: Lukasz Radziejewski

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

Image: Avinash Kumar

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

Image: United States Treasury Department, Public domain, via Wikimedia Commons

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?

Image: The original uploader was Durova at English Wikipedia., Public domain, via Wikimedia Commons

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

Image: Quilia

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)

Image: Money Knack

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

Image: Logan Voss

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.

Geography Geography 5 min read

Stories carved by the Colorado River

The missing pieces of the Grand Canyon: 10 incredible facts

Image: jesus esteban

The Grand Canyon is bigger than Rhode Island. It's deeper than four Empire State Buildings stacked end to end. Its rocks are older than dinosaurs. But those stats alone don’t quite capture its immensity — and are hardly the most shocking. There are nuclear shelters, hidden villages, and billion-year mysteries involved. Read on to learn 10 lesser-known facts about the Grand Canyon.

1
There's an unexplained billion-year gap

Image: John Graybosch

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

Image: Lauri Väin from Tallinn, Estonia, CC BY 2.0, via Wikimedia Commons

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

Image: Alexandre Henry Alves

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

Image: abdurrohman dzar

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

Image: Abhishek Navlakha

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

Image: MARIOLA GROBELSKA

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

Image: AussieActive

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

Image: Naeemphotographer2

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

Image: Alexander Wong

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

Image: joojoob27

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.

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