Original image
Getty Images

Underground America: 7 Things You Could Be Standing on

Original image
Getty Images

By Richard Faulk

You just never know what you might be standing on. We asked the author of Gross America: Your Coast-to-Coast Guide to All Things Gross to see what he could dig up.


The Embarcadero, San Francisco  The Gold Rush of 1849 made San Francisco’s population explode. Many gold-crazed argonauts sailed in on wooden ships, and hundreds of these were abandoned in Yerba Buena Cove when fortune-seeking crews jumped ship to try their luck in the mining camps too. As the land-starved city expanded by filling in its marshy coastline, many of these abandoned vessels were converted to underground store-rooms, saloons, brothels, and even jails servicing the disorderly denizens of the Barbary Coast. Ever since, construction projects have periodically uncovered these ghostly remains. As recently as 2005, a ship was discovered beneath Folsom Street.


Paisley Caves, Oregon — For decades, the 13,000-year-old Clovis spear points of New Mexico were thought to be the oldest traces of human life in the Americas. But, in 2002, anthropologists from the University of Oregon discovered 25 human coprolites—fossilized poop to the rest of us—in a network of prehistoric caves in south Oregon. Seeds, bone, and thread embedded in the fossils provide invaluable clues to the caveman culture and cuisine. Some are at least 14,700 years old, and scientists consider this to be the oldest evidence of human life in North America.


Wabaunsee County, Kansas — Ever dream of living like Dr. No, in an ultra-modern under- ground lair with intercontinental nuclear capability? You could do what Edward and Dianna Peden of Topeka did and buy your own decommissioned Cold War–era missile silo (missile not included). When the Pedens acquired the home they now call Subterra Castle, it wasn’t exactly a supervillain bachelor pad. Decades of flooding and disuse had given the former launch control center the charm of a subway lavatory. Bought for $40,000, the converted living space now vibrates with an “eclectic spirit of peace.” At press time, there was a similar 2,300-sq.-ft. silo in upstate New York available for a cool $3 million.


Crystal Falls, Michigan — Spread across 38 acres of north Michigan forest, and clocking in at up to 10,000 years old, the 100-ton colony of Armillaria bulbosa, or honey mushroom, is one of the world’s oldest and largest living organisms. It was discovered in 1988, but it took a 1992 article in Nature magazine to turn it into a sensation. Ever since, the enterprising folk of Crystal Falls have held an annual Humongous Fungus Fest. Would-be fungus spotters are inevitably disappointed that the bulk of the Armillaria are underground rhizomorphs—all that’s visible above the dirt are ordinary looking button mushrooms. But at least there’s a parade, pancakes, and an Elvis impersonator.


South Pennsylvania — Surrounded by razor wire and guard posts, bristling with communications towers, and accessed via multiple concrete-faced, iron-doored tunnels, Raven Rock Mountain Complex is top secret but hardly inconspicuous. Conceived during the Truman Administration as a backup Pentagon, the hollowed-out greenstone mountain six miles north of Camp David is rumored to contain power plants, a reservoir, and five 3-story office buildings—the facilities could shelter 3,000 people in the event of a national cataclysm. After 9/11, it was one of several secret locations where Vice President Dick Cheney was sequestered.


Arlington, Virginia — Between 1972 and 1973, reporter Bob Woodward met six times with a source known as Deep Throat, who provided inside information about the Watergate break-in, the scandal that would bring down the Nixon Administration. For 30 years, Deep Throat’s identity remained a mystery, until former FBI official Mark Felt outed himself in 2005. Woodward confirmed it—and also revealed where the two used to meet: space 32D on the lower level of an Arlington garage at Wilson Boulevard and Nash Street.


Waxahachie, Texas — Beneath the rolling prairie outside Dallas lies the Alamo of our nation’s grand ambitions in particle physics. Approved in the late 1980s with a budget of $4.4 billion, the Superconducting Super Collider was going to use magnets to accelerate protons around an underground ring 52 miles in diameter, and then smash them together with a force 20 times greater than ever before. Scientists planned to monitor the ensuing debris for exotic subatomic particles, like the highly sought Higgs boson. But in 1993, when projected costs grew in excess of $11 billion, Congress balked. The SSC was summarily terminated, but not before $2 billion was spent and 15 miles of tunnel were dug. In 2012, Geneva’s much smaller Large Hadron Collider discovered the Higgs boson, which led to a Nobel Prize in physics. Score one for Switzerland.

This piece originally appeared in an issue of mental_floss magazine. Subscribe here.

Original image
iStock // Ekaterina Minaeva
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
Original image
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!

Original image
Live Smarter
Working Nights Could Keep Your Body from Healing
Original image

The world we know today relies on millions of people getting up at sundown to go put in a shift on the highway, at the factory, or in the hospital. But the human body was not designed for nocturnal living. Scientists writing in the journal Occupational & Environmental Medicine say working nights could even prevent our bodies from healing damaged DNA.

It’s not as though anybody’s arguing that working in the dark and sleeping during the day is good for us. Previous studies have linked night work and rotating shifts to increased risks for heart disease, diabetes, weight gain, and car accidents. In 2007, the World Health Organization declared night work “probably or possibly carcinogenic.”

So while we know that flipping our natural sleep/wake schedule on its head can be harmful, we don’t completely know why. Some scientists, including the authors of the current paper, think hormones have something to do with it. They’ve been exploring the physiological effects of shift work on the body for years.

For one previous study, they measured workers’ levels of 8-OH-dG, which is a chemical byproduct of the DNA repair process. (All day long, we bruise and ding our DNA. At night, it should fix itself.) They found that people who slept at night had higher levels of 8-OH-dG in their urine than day sleepers, which suggests that their bodies were healing more damage.

The researchers wondered if the differing 8-OH-dG levels could be somehow related to the hormone melatonin, which helps regulate our body clocks. They went back to the archived urine from the first study and identified 50 workers whose melatonin levels differed drastically between night-sleeping and day-sleeping days. They then tested those workers’ samples for 8-OH-dG.

The difference between the two sleeping periods was dramatic. During sleep on the day before working a night shift, workers produced only 20 percent as much 8-OH-dG as they did when sleeping at night.

"This likely reflects a reduced capacity to repair oxidative DNA damage due to insufficient levels of melatonin,” the authors write, “and may result in cells harbouring higher levels of DNA damage."

DNA damage is considered one of the most fundamental causes of cancer.

Lead author Parveen Bhatti says it’s possible that taking melatonin supplements could help, but it’s still too soon to tell. This was a very small study, the participants were all white, and the researchers didn't control for lifestyle-related variables like what the workers ate.

“In the meantime,” Bhatti told Mental Floss, “shift workers should remain vigilant about following current health guidelines, such as not smoking, eating a balanced diet and getting plenty of sleep and exercise.”