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Robin Esrock

Incredible Photos of the World's Scariest Hike

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Robin Esrock

This story originally appeared in print in the August issue of mental_floss magazine. Subscribe to our print edition here, and our iPad edition here.

The world's scariest hike is more than an internet meme—it's a 7,000-foot-high cliffside trail in China that will take your breath away.


It was the uncredited photo of wooden planks
stapled to the mountain that got my attention. The whole setup looked so precarious. And while I couldn’t tell just how high the planks were, the snow-capped mountains peering from the distance gave some indication.

Ever since the picture hit my inbox—an email forward from a friend—I couldn’t get it out of my mind: Could a place like this really exist? Could people really go there?

I needed to find out. A few hours of online sleuthing proved that the photo was real. The path does exist, on a mountain called Huashan, 75 miles from one of China’s historical capitals of Xi’an. So I booked a flight.

The city is a popular destination for international tourists. Some make the 90-minute drive to Mount Hua, but few would think about scaling the mountain’s cliffside plank path. The Chinese, on the other hand? They’re not so easily deterred.

Every year, millions of Chinese make pilgrimages to the Five Great Mountains, Taoist landmarks that have long featured in legends, history, and art. Besides being naturally stunning, the mountains are dotted with temples, teahouses, and plenty of opportunities for reflection and prayer. Hua is China’s West Great Splendid Mountain, and it attracts thousands of visitors daily.

I arrive to find a parking lot full of domestic tour buses, with cable cars ferrying traffic to the base. Innocuous enough, although the optional insurance for purchase with my day ticket suggests this isn’t going to be a walk in the park. “We don’t encourage foreign tourists to visit Huashan,” a guide tells me. “Too dangerous.”

But the path, known locally as No. 1 Steep Road on Mount Hua, requires no actual climbing experience. From the base, steep steps are carved directly into rock. Their proximity to the edge, overlooking a 3,200-foot drop, doesn’t rattle the cheery tourists visiting that day.

There are no hiking boots in sight. Instead, the only gear present is the thin white gloves everyone seems to wear as they hold onto the cold, heavy iron chains that bracket the paths.

It was hot and humid in Xi’an this morning, but here, snow dusts the trees, and Mount Hua’s 7,000-foot elevation has frozen the air. The higher I walk, the more I wish I was wearing more than just a thin sweater. But I’ve come a long way, and the signs in poor English keep urging me forward.

Robin Esrock

My destination, the cliffside plank path, is located between the south and east peaks. After an hour of walking, tourist traffic peters out. I exit a beautiful temple, walk around a boulder, and almost spew my pistachio snack. The view is extraordinary, and the narrow path beckons. From this point on, safety harnesses are required—I fork over the equivalent of $5 for one and a set of caribiners. My hands are freezing, and in an act of compassion, the attendant takes off his thin white gloves and gives them to me.

Iron bars are hammered into a crevice, and I scale down them slowly, not eager to test these caribiners. A few feet down, I reach the thin, cracked planks on the rock face. It looks just like the photo. Clipping on to the chain above, I shuffle along the wood, overwhelmed by the silence, the mountains, the beauty, the cold. A two-inch plank of wood is all that separates me from the void.

After a few minutes, I hear giggles from the crevice above. A half dozen students emerge, amused to find a foreigner on the path. We take some pictures together and walk carefully to the end of the planks, where we find a small temple in a cave. I presume this is where one offers thanks for making it alive. To get back, I will have to once again brave the planks. This time there are more students making their way from the other side. Detaching our safety harnesses, we squeeze past one another, vulnerable to balance, strong wind, creaky wood, and battered nerves. Somehow, we make it.

Robin Esrock

I return the gloves to the attendant and stroll back along the solid cement trail to buy some tea to warm my chilled bones. Is this the world’s scariest hike? Perhaps not. But it’s certainly close enough to the edge for me.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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8 Common Dog Behaviors, Decoded
May 25, 2017
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iStock

Dogs are a lot more complicated than we give them credit for. As a result, sometimes things get lost in translation. We’ve yet to invent a dog-to-English translator, but there are certain behaviors you can learn to read in order to better understand what your dog is trying to tell you. The more tuned-in you are to your dog’s emotions, the better you’ll be able to respond—whether that means giving her some space or welcoming a wet, slobbery kiss. 

1. What you’ll see: Your dog is standing with his legs and body relaxed and tail low. His ears are up, but not pointed forward. His mouth is slightly open, he’s panting lightly, and his tongue is loose. His eyes? Soft or maybe slightly squinty from getting his smile on.

What it means: “Hey there, friend!” Your pup is in a calm, relaxed state. He’s open to mingling, which means you can feel comfortable letting friends say hi.

2. What you’ll see: Your dog is standing with her body leaning forward. Her ears are erect and angled forward—or have at least perked up if they’re floppy—and her mouth is closed. Her tail might be sticking out horizontally or sticking straight up and wagging slightly.

What it means: “Hark! Who goes there?!” Something caught your pup’s attention and now she’s on high alert, trying to discern whether or not the person, animal, or situation is a threat. She’ll likely stay on guard until she feels safe or becomes distracted.

3. What you’ll see: Your dog is standing, leaning slightly forward. His body and legs are tense, and his hackles—those hairs along his back and neck—are raised. His tail is stiff and twitching, not swooping playfully. His mouth is open, teeth are exposed, and he may be snarling, snapping, or barking excessively.

What it means: “Don’t mess with me!” This dog is asserting his social dominance and letting others know that he might attack if they don’t defer accordingly. A dog in this stance could be either offensively aggressive or defensively aggressive. If you encounter a dog in this state, play it safe and back away slowly without making eye contact.

4. What you’ll see: As another dog approaches, your dog lies down on his back with his tail tucked in between his legs. His paws are tucked in too, his ears are flat, and he isn’t making direct eye contact with the other dog standing over him.

What it means: “I come in peace!” Your pooch is displaying signs of submission to a more dominant dog, conveying total surrender to avoid physical confrontation. Other, less obvious, signs of submission include ears that are flattened back against the head, an avoidance of eye contact, a tongue flick, and bared teeth. Yup—a dog might bare his teeth while still being submissive, but they’ll likely be clenched together, the lips opened horizontally rather than curled up to show the front canines. A submissive dog will also slink backward or inward rather than forward, which would indicate more aggressive behavior.

5. What you’ll see: Your dog is crouching with her back hunched, tail tucked, and the corner of her mouth pulled back with lips slightly curled. Her shoulders, or hackles, are raised and her ears are flattened. She’s avoiding eye contact.

What it means: “I’m scared, but will fight you if I have to.” This dog’s fight or flight instincts have been activated. It’s best to keep your distance from a dog in this emotional state because she could attack if she feels cornered.

6. What you’ll see: You’re staring at your dog, holding eye contact. Your dog looks away from you, tentatively looks back, then looks away again. After some time, he licks his chops and yawns.

What it means: “I don’t know what’s going on and it’s weirding me out.” Your dog doesn’t know what to make of the situation, but rather than nipping or barking, he’ll stick to behaviors he knows are OK, like yawning, licking his chops, or shaking as if he’s wet. You’ll want to intervene by removing whatever it is causing him discomfort—such as an overly grabby child—and giving him some space to relax.

7. What you’ll see: Your dog has her front paws bent and lowered onto the ground with her rear in the air. Her body is relaxed, loose, and wiggly, and her tail is up and wagging from side to side. She might also let out a high-pitched or impatient bark.

What it means: “What’s the hold up? Let’s play!” This classic stance, known to dog trainers and behaviorists as “the play bow,” is a sign she’s ready to let the good times roll. Get ready for a round of fetch or tug of war, or for a good long outing at the dog park.

8. What you’ll see: You’ve just gotten home from work and your dog rushes over. He can’t stop wiggling his backside, and he may even lower himself into a giant stretch, like he’s doing yoga.

What it means: “OhmygoshImsohappytoseeyou I love you so much you’re my best friend foreverandeverandever!!!!” This one’s easy: Your pup is overjoyed his BFF is back. That big stretch is something dogs don’t pull out for just anyone; they save that for the people they truly love. Show him you feel the same way with a good belly rub and a handful of his favorite treats.

The best way to say “I love you” in dog? A monthly subscription to BarkBox. Your favorite pup will get a package filled with treats, toys, and other good stuff (and in return, you’ll probably get lots of sloppy kisses). Visit BarkBox to learn more.

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