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.

Secrets of heights

Unsolved mysteries, strange finds, and fossils: The truth about Everest

Image: Martin Jernberg

At 29,032 feet, Mount Everest is known as the "rooftop of the world." While that's a fact most people already know, this ancient mountain holds more secrets than you might expect. From mythical creatures to the most unusual objects ever found there, today we're taking a journey up Everest, and what we'll discover might surprise you!

Image: Ben Lowe

Most of us know it simply as Everest, but this mountain has more identities. In the 19th century, the British named it after Sir George Everest, a British surveyor. But in Nepal, it's called Sagarmatha, which means "Forehead of the Sky." In Tibet, meanwhile, it's known as Chomolungma, meaning "Goddess Mother of the World." Beautiful, right?

Image: Konstantin Mishchenko

If you think marriage is only for the daring, you won't believe this. Despite the danger and harsh weather, several couples have chosen the world's highest peak as the location for their wedding. A recent example is Ashley Schmieder and James Sissom, who in 2017 became the first couple to get married on the summit of Everest wearing traditional wedding outfits. Imagine wearing a wedding dress at -10°F!

Image: Sebastian Pena Lambarri

On average, 800 to 900 people try to climb Everest each year, with many more visiting its base. Along the way, climbers often leave behind a surprising amount of items like crampons, clothing, cooking utensils, climbing tools, and oxygen bottles. In fact, there are "Trash zones" filled with these and many other articles left behind by people. You can imagine what else might be found there, especially since not everyone makes it to the summit.

Image: Joseph Corl

At the top of Everest, there's more than just leftover climbing gear. There, at almost 30,000 feet above sea level, they have found something else: marine fossils!

Although the summit is far from the sea today, it wasn't always that way. Millions of years ago, the area where Everest now stands was once part of a seabed at the bottom of the ocean. Over time, tectonic plates pushed the land upward, forming not just Everest but the entire Himalayan mountain range.

Image: Jonathan Ansel Moy de Vitry

Experienced climbers typically take 6 to 9 weeks to reach the summit of Everest, something incredible given the mountain's extreme conditions. But hear this: In 2003, expert Nepalese climber Lakpa Gelu reached the summit in just 10 hours and 56 minutes. And as if that wasn't impressive enough, in 2004, Sherpa Pemba Dorje beat that record, making it to the top in only 8 hours and 10 minutes!

Image: Luo Lei

The movement of tectonic plates causes the Himalayas to rise. Incredible as it may seem, Mount Everest isn't just tall: It's actually growing a fraction of an inch every year! It may not sound like much, but over millions of years, it really adds up.

Image: Ehab Al-Hakawati

There's an unsolved mystery on Everest involving two British climbers, George Mallory and Andrew Irvine, who aimed to be the first to reach the summit back in 1924. They were reportedly last seen close to the top, but no one knows if they actually made it.

Both climbers disappeared, and while Mallory's body was discovered in 1999, Irvine has never been found. Many people report encountering ghosts that haunt the mountain and sometimes even offer help. Could those spirits be the two of them?

Image: Kirsten Frank

In 2024, Nat Geo explorers found a boot with a sock inside that read "A. C. Irvine." That's right! It took a hundred years before they finally discovered this boot, believed to have belonged to Irvine.

If it took a century to find just one boot, imagine everything else that might still be up there!

Image: Agnès Maillard

Part of the mountain's folklore is the mythical Yeti, also known by his stage name: the Abominable Snowman. Reports of a huge, ape-like creature walking on two legs date back as early as the 19th century.

Most research suggests it's likely all about a bear species, but even today, some people still claim to have seen the Yeti. In the mountain, there have also been discoveries of footprints too large to be human, and even enormous bones!

Image: JC Gellidon

The extreme altitude, cold, and other harsh conditions make life on Everest tough. However, to many people's surprise, the mountain does have its own unique plants and animals, all known for their ruggedness. On one hand, you can find hardy plants like mosses, lichens, and the Himalayan Blue Poppy. When it comes to animals, the area is home to snow leopards, Himalayan tahr (wild goats), and yaks. Of course, the higher you go, the scarcer wildlife becomes.