Secret uses

This is how a tiny hole in an elevator door can save your life

You’ve probably twisted a bread bag closed, filled up your car, or pulled a sheet of aluminum foil from the box thousands of times without giving it a second thought. But many of the everyday objects we’ve used for decades have clever features that most people never notice. From the tiny pocket on blue jeans to the little arrow next to your gas gauge, these hidden designs have practical stories behind them, and once you know them, you’ll never look at these familiar items the same way again.

If you own an iPhone, you’ve probably noticed the tiny black dot next to the rear camera. It’s small, so people tend to assume it’s another camera sensor or even part of the phone’s design. The small hole found near the camera bump on every iPhone is actually a rear microphone.

It captures clearer audio when you’re recording videos and helps reduce background noise during FaceTime and regular phone calls. If you own an iPhone Pro model from the iPhone 12 Pro onward, you'll also see a larger dark circle. That’s the LiDAR scanner, which sends out invisible infrared light to create a 3D map of your surroundings. It helps the camera focus faster in low light, powers Apple’s Measure app, and makes augmented reality features much more accurate.

Whether it's a holiday dinner, an anniversary, or simply a nice meal with friends, you’ve probably held a wine bottle and noticed the deep indentation in the bottom. Many people tend to think the deeper the indent, the fancier the bottle.

That indentation is called a punt, and it’s been a part of the bottle-making for centuries. Originally, it helped strengthen hand-blown glass bottles, making them less likely to crack under pressure. Today, it still adds structural stability, particularly for sparkling wines, while also giving servers a comfortable place to rest their thumb when pouring, though some say it helps collect the sediment as wines age. In any case, a deeper pun doesn’t automatically mean a better or more expensive bottle.

Almost every driver has experienced that awkward moment at the gas station. You pull up to the pump, step out of the car, and suddenly realize the fuel door is on the opposite side.

To help prevent exactly that situation, many modern vehicles include a small arrow next to the gas pump symbol on the dashboard’s fuel gauge. The arrow points towards the side of the vehicle where the fuel filler door is located. It’s a small detail on the dashboard, yet once you notice it, you’ll never have to circle the pump again.

All elevators look pretty much the same. Bigger or smaller, they all look similar, a gray box with a mirror and buttons. But if you pay close attention, you may notice there’s a small round opening near the top of the door.

That opening is a keyhole used by trained maintenance technicians and emergency responders. With a special elevator key, they can manually unlock the landing doors when repairs are needed or if passengers become trapped inside. The system allows professionals to reach the elevator safely without damaging the doors or relying solely on electrical controls. Hopefully, most of us will never need to see it in action. But in an emergency, that tiny opening becomes one of the most important parts of the system.

If you’ve ever stood in the bread aisle comparing loaves, you’ve probably noticed the colorful plastic clips or twist ties holding the bags shut. Contrary to what many think, they’re not simply a part of the packaging.

For many bakeries and grocery stores, the colors indicate the day a loaf was delivered or baked. While the exact color schedule can vary between bakeries and regions, employees use the system to quickly spot older inventory and rotate fresher bread to the back of the shelf. That way, customers are more likely to pick up the freshest loaf available.

Whether you wear jeans every day or only pull them out for yard work, you’ve probably noticed the tiny extra pocket tucked inside one of the front pockets. It’s too small for a phone and not very useful for loose change, but there’s a reason for it.

Back in the 1800s, when Levi Strauss & Co. created rugged denim pants for miners, ranchers, and cowboys working across the American West, pocket watches were commonplace. Workers needed a safe place to carry their watches while riding horses, so that little pocket was designed specifically to protect the watch from damage. Pocket watches disappeared, but the tiny pocket became such an iconic part of blue jeans that manufacturers have continued including it for well over a century.

Almost everyone has had the same frustrating experience. You pull on a sheet of aluminum foil, and suddenly the entire roll slides out of the box and lands on the kitchen counter.

That’s exactly why major manufacturers such as Reynolds introduced the small side tabs, known as end locks, in the mid-1990s. By pressing the tabs inward, they hold the cardboard roll in place like built-in axles. This keeps the roll from sliding out of the box, makes it much more stable as you pull, and helps the serrated edge cut a cleaner, straighter sheet. It also reduces waste by preventing the foil from bunching up or tearing unevenly. It’s a simple design, yet useful as it can get.

Every household has pens lying around for all kinds of purposes. And most of them have a common feature, a hole in the cap, which isn’t simply part of the design.

BIC and other pen manufacturers included the opening as a safety feature. If someone, especially a child, accidentally swallows a pen cap, the hole can allow a small amount of air to pass through, reducing the risk of complete airway blockage while emergency help is on the way. The design became part of border efforts to improve consumer product safety after choking incidents drew attention to the danger of small plastic objects.

If you grew up sewing or watching somebody do it, you probably remember the classic tomato-shaped pincushion sitting beside the sewing basket. Hanging from it was a tiny red strawberry that looked like nothing more than a cute finishing touch.

In reality, that little strawberry has its own job. Instead of soft stuffing, it’s filled with emery, a gritty material made from crushed abrasive minerals. Running pins and needles through it helps polish away tiny spots of rust, smooth rough edges, and keep the points sharp enough to glide through fabric more easily.

Think back to the first time you learned to type. Maybe it was at work, or on a family computer. Wherever it was, someone probably told you to keep your fingers on the "home row." That’s exactly why the F and J keys have tiny raised ridges.

The bumps let your index fingers find the correct starting position by touch alone, allowing you to type without constantly looking down at the keyboard. The technique, known as "touch typing," is widely credited to American court stenographer Frank Edward McGurrin, who demonstrated it in 1888. As typewriters became more common, manufacturers experimented with different ways to help typists orient their hands, and by the mid-20th century, companies such as IBM standardized the subtly raised plastic bars that remain on nearly every keyboard today.

10 weird historical events that no one has been able to explain (yet)

Image: Walters Art Museum, Public domain, via Wikimedia Commons

Who doesn't like a good mystery? And if the mystery isn’t a work of fiction but the result of a true story, even better! The great unsolved enigmas of history are absolutely fascinating. Some have been solved over time, but there are still many old secrets for which neither scientists nor historians have found an explanation—yet. Time-travel with us as we uncover 10 of the biggest historical mysteries that will probably never be cracked!

Image: Tanner, Henry S., Public domain, via Wikimedia Commons

Bermeja Island is mentioned in navigation texts written by European travelers and appears in cartography from the 16th to 19th centuries. Old maps place it off the north coast of the Yucatán Peninsula; however, multiple searches over the years have yielded no concrete evidence of its existence.

So, what happened to Isla Bermeja? Was it a cartographic error? Did it sink due to a tidal wave? Because of its geopolitical significance, some have even suggested that it was blown up by the CIA! A 2009 study by the Autonomous University of Mexico concluded that Isla Bermeja does not exist today, nor were any traces found at its supposed coordinates. Yet, it will forever remain a mystery that will surely keep many entertained.

Image: Credit: Big Ear Radio Observatory and North American AstroPhysical Observatory (NAAPO)., Public domain, via Wikimedia Commons

In 1977, Ohio State University’s Big Ear radio telescope, used in the search for extraterrestrial intelligence, detected a signal now known as the Wow! signal. While reviewing the data, astronomer Jerry R. Ehman noticed a sequence represented as "6EQUJ5." Baffled by the anomaly, he circled it and wrote "Wow!" in the margins.

The signal lasted 72 seconds and, unfortunately, has never been repeated. To this day, no one can fully explain the phenomenon, although some suggest it may have come from a man-made source. Still, the Wow! signal remains one of the strongest candidates for potential extraterrestrial contact ever detected.

Image: Edward S. Curtis, Public domain, via Wikimedia Commons

How is it possible for an entire village to vanish without a trace? Believe it or not, this is said to have happened nearly a century ago. According to lore, a small Inuit village in Canada was well known among fur trappers who visited regularly to trade. But in 1930, something very strange supposedly occurred.

A hunter named Joe Labelle claimed he visited the village one day and couldn’t find a single person. Reports said there were guns and food left behind, and even claims that the graves in the cemetery were empty. A thorough investigation, however, found no conclusive evidence of what happened to the villagers. Some witnesses from nearby towns even reported seeing a huge green light. Theories ranged from mass migration to extraterrestrial abductions. The Royal Canadian Mounted Police has since dismissed the case as an urban legend. Some still believe the story to be true.

Image: bbb

We know thousands of shipwreck stories, but this one is quite unique. The MV Joyita, designed to be nearly unsinkable, was found adrift in the South Pacific, practically unharmed, but the crew had disappeared completely.

In October 1955, the American merchant vessel left the port of Apia in Samoa with 16 crew members and 9 passengers bound for the Tokelau Islands. After days without news, a rescue mission was launched. Five weeks later, the Joyita was spotted more than 600 miles west of its intended route. The vessel was partially submerged, and there was no sign of the passengers or crew. Four tons of cargo and all three life rafts were missing. They were never seen again.

Image: Gary Todd from Xinzheng, China, CC0, via Wikimedia Commons

Do you know where one of the best-preserved mummies was found? Hint: not in Egypt. Xin Zhui, the Marquise of Dai during the Western Han Dynasty in China, was discovered in her tomb at Mawangdui 2,000 years after her death, along with hundreds of valuable documents and artifacts.

What makes this mummy so extraordinary is how well-preserved her body is. Her organs and veins remain intact, and she still has hair and even eyelashes. Scientists analyzed the fluid present in the coffin and discovered it was acidic and contained salt and magnesium. They believe this mysterious liquid may have been responsible for preserving Xin Zhui so well. What they don’t know is whether it was intentionally poured into the coffin or came from the body itself.

Image: Yoichi Okamoto, Public domain, via Wikimedia Commons

The United States has its fair share of presidents who died while in office, but none of our 45 presidents have ever disappeared without a trace. Did you know that this actually happened in The Land Down Under?

Harold Edward Holt was the Prime Minister of Australia from 1966 until his presumed death in 1967. He loved the ocean and spearfishing. During a weekend trip with friends, Holt visited the remote Cheviot Beach to take a swim. Rough sea conditions that day caused him to be swept away by the waves, and he never reappeared. Despite an intensive search, his body was never found, which has given rise to numerous conspiracy theories. Ironically, Australians built the Harold Holt Memorial Swimming Centre in Melbourne in his honor.

Image: FBI, Public domain, via Wikimedia Commons

Many famous criminals have managed to remain unidentified for decades, but the D.B. Cooper case is something else entirely. In 1971, Cooper boarded a flight from Portland to Seattle. Shortly after takeoff, he showed a flight attendant a device he claimed was a bomb and demanded four parachutes and $200,000 in cash.

The crew landed to meet Cooper’s demands in exchange for the passengers and then took off again. As the plane flew over southwestern Washington, Cooper jumped into the cold, rainy night carrying his haul. His whereabouts and true identity were never discovered, although it is likely he didn’t survive the jump. In 1980, some of the ransom money was found near the Columbia River. Although the FBI officially closed the case in 2016, amateur sleuths continue to try to crack it.

Image: Pieter Brueghel the Elder, Public domain, via Wikimedia Commons

Can you imagine an epidemic where the main symptom is uncontrollable dancing? Sounds like science fiction, doesn’t it? Yet this really happened during the Middle Ages. In 1518, a dancing plague struck Strasbourg, Alsace, in what is now France. This strange condition affected up to 400 people, making them dance frantically for weeks. It is said that some even died of heart attacks, exhaustion, or strokes.

Doctors and authorities tried all kinds of measures to stop the spread. They even banned music for a while! To this day, scientists are not certain what caused this bizarre condition: it may have been food poisoning from toxins in the ergot fungus, or perhaps a case of stress-induced mass hysteria.

Image: Public domain, via Wikimedia Commons

The Voynich manuscript is a codex written roughly 500 years ago in an unknown language and writing system by an anonymous author. Known as Voynichese, the manuscript was named after Wilfrid Voynich, a Polish bibliophile and antiquarian who purchased it in 1912.

Radiocarbon testing has shown that it dates to the early 15th century. Many cryptographers and codebreakers have attempted to decipher its roughly 240 pages without success. The manuscript contains diagrams and illustrations of unknown plants and astrological symbols. Some believe it may be a made-up language, a secret code, a work of fiction, or even a hoax. If you think you can solve this mystery, the Voynich manuscript is available for viewing at Yale University’s Beinecke Rare Book and Manuscript Library.

Image: Bernhard

Similar to the Voynich manuscript, the Phaistos Disc is a fired clay disc believed to have been created during the Bronze Age. It was discovered by an Italian archaeologist in the basement of a palace in Crete, Greece, in 1908.

What makes this disc fascinating is that it contains a mysterious message. Stamped into the clay is a set of signs, forming a text that many scientists have tried to decipher—without success. It is considered an early attempt at printing, a technological innovation that would not become widespread for several centuries. While enthusiasts still hope the enigma can be solved, this is unlikely unless other documents are discovered to provide context.