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13 Straight Facts About the Leaning Tower of Pisa

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The Leaning Tower of Pisa may be the world's greatest spot for a tourist photo, but there's a lot more to this centuries-old icon than lighthearted images of your friends and family "holding up" the tower. Here's everything you need to know about Italy's most beloved architectural accident.

1. IT TOOK TWO CENTURIES TO BUILD IT.

Construction on a campanile, or bell tower, to accompany the public cathedral in the Italian riverside city of Pisa broke ground in August 1173. By 1178, workers had made it to the third story of the structure, which was already tilting slightly to the north. Military conflicts with other Italian states would soon halt progress on the tower, which would not resume until 1272. This time, construction only remained underway for 12 years before another war again stopped the work. A final wave of construction picked up again in the early 14th century, concluding with the installation of a bell chamber in 1372.

2. THE TOWER LEANS BECAUSE OF ILL-CONCEIVED DESIGN PLANS. 

While some architectural follies are the product of unforeseeable bouts of bad luck, the Leaning Tower of Pisa’s signature tilt could have been avoided with better planning. A shallow foundation and the soft ground of Pisa—composed of sand, clay, and deposits from the Tuscan rivers Arno and Serchio—were too unstable to support the building even in the early stages of its construction. Amazingly, the builders noticed this error early in the two-century construction project—after the addition of a second story to the tower, the ground began to give, prompting that infamous slant. 

3. AT ONE POINT, THE TOWER’S LEAN SWITCHED DIRECTIONS.

When construction resumed in 1272, the additional developments did not exactly help the tower’s posture. The stacking of additional stories atop the existing three jostled the building’s center of gravity, causing a reversal in the direction of its tilt. As the tower accrued its fourth, fifth, sixth, and seventh stories, the once northward-leaning structure began to tip further and further south

4. THE LEAN KEPT GETTING PROGRESSIVELY WORSE.

As time passed, the ground only further weakened beneath the tower’s heft. An early 0.2-degree tilt increased gradually over the subsequent centuries, maxing out at 5.5 degrees—or with the top 15 feet south of the bottom—by 1990. Over the next decade, a team of engineers leveled the soil beneath the tower and introduced anchoring mechanisms in an effort to rectify the landmark’s nearly catastrophic lean. The project allotted the tower a more secure stance, but it did not prevent continued tipping. By 2008, however, a second go at balancing the foundational soil halted the tower’s continued slouching for the first time ever. 

5. THE ENGINEER WHO OVERSAW THIS RECLAMATION PROJECT WASN’T ALWAYS AN EXPERT IN THE FIELD.

John Burland wasn’t exactly a prime candidate for a project like solidifying the Leaning Tower of Pisa on paper. Burland admits that soil mechanics, the area of engineering that played a pivotal role in the stabilizing of the tower, was his worst subject during his undergraduate studies at University of the Witwatersrand, Johannesburg. He ultimately overcame his aversion to this subject to become a professor at Imperial College London (and saved the Leaning Tower of Pisa from complete collapse, of course). 

6. THE TOWER COULD STILL RESUME TILTING. 

Barring additional efforts to prevent future leaning, the tower is predicted to remain stable only for the next 200 years. If everything else remains constant, the ground should begin giving way again in the early 23rd century, allowing for the tilt to slowly resume

7. THE LEANING TOWER OF PISA IS JUST ONE OF SEVERAL LEANING TOWERS IN PISA. 

A number of other Pisani structures suffer foundational instability thanks to the river city’s soft grounds. Among these are San Nicola, a 12th century church located about half a mile south of the Leaning Tower of Pisa, and San Michele degli Scalzi, an 11th century church about two miles east of the pair. While San Nicola, whose base is rooted beneath the earth, leans only mildly, San Michele degli Scalzi boasts a substantial 5-degree tilt. 

8. OTHER TOWERS HAVE CHALLENGED ITS FAMED LEAN.

No building on Earth is more famous for its diagonal posture than the Leaning Tower of Pisa, but several others have challenged its superlative slant. In 2009, the Leaning Tower of Surhuusen, a German steeple erected between the 14th and 15th centuries, officially “out-leaned” its Pisani rival—Guinness record keepers calculated that the Surhuusen tower’s tilt extended a full 1.2 degrees further than that of Pisa’s, which had been modified from its pre-1990s peak of 5.5 degrees to a less-drastic 3.97 degrees. Another German tower, the town of Bad Frankenhausen’s 14th century church Oberkirche, and the shorter of the Two Towers of Bologna have also bested the Pisa tower with 4.8-degree and 4-degree leans, respectively. 

9. MUSSOLINI TRIED TO FIX THE TOWER. HE ONLY MADE IT WORSE. 

In 1934, Italian dictator Benito Mussolini declared the crooked attraction was a pockmark on his nation’s reputation and allocated resources for straightening the building. Mussolini’s men drilled hundreds of holes into the tower’s foundation and pumped in tons of grout in a misguided effort to rectify its tilt. Instead, the heavy cement caused the base of the tower to sink deeper into the soil, resulting in an even more severe lean. 

10. THE TOWER WAS A MILITARY BASE DURING WORLD WAR II. 

Even though the tower’s distinctive silhouette would seem to make it an easy target, the German army felt it was a prime lookout point during World War II because the tall tower provided optimal surveillance over the surrounding flat terrain. 

11. AMERICAN TROOPS DECIDED NOT TO DESTROY THE TOWER. 

The German use of the tower nearly succeeded where gravity has failed in bringing the tower down. When the advancing U.S. Army was charged with demolishing all enemy buildings and resources in 1944, soldiers were too spellbound by the iconic tower’s aesthetic charms to call in artillery to bring it down. As detailed by veteran Leon Weckstein in a 2000 interview with The Guardian, the American troops braving the terrains of Axis-occupied Pisa were so entranced by the sight of the Leaning Tower that they couldn’t call for the volley of fire. Weckstein recalls preparing to attack the Nazi base before ultimately retreating and leaving the beautiful tower intact. 

12. GALILEO MAY NOT HAVE DROPPED A CANNONBALL FROM THE TOP. 

Among Renaissance physicist Galileo Galilei’s most famous achievements was the discovery that gravity’s effect on an object is the same regardless of its mass. This epiphany is said to have hit Galileo atop the Leaning Tower of Pisa, from where he allegedly dropped a cannonball and a musket ball in 1589. The scientist’s biography, penned by disciple Vincenzo Viviani, remains the sole official assertion that such an experiment took place. 

Modern scholars like Paolo Palmieri and James Robert Brown argue that the Leaning Tower of Pisa test existed only as a thought experiment of Galileo’s—devised perhaps at a much later chapter in his life—and was never carried out but was inflated by Viviani to buff the grandeur of Galileo’s discovery. 

13. A ROCK DOME IN ANTARCTICA IS NAMED AFTER THE TOWER. 

Despite having been discovered by the French Antarctic Expedition, a particularly hefty rock dome in the seventh continent’s Geologie Archipelago is named for Italy’s prized tower. The 27-meter-long formation, first documented on Rostand Island in 1951, goes by the nickname of “Tour de Pise” thanks to its resemblance to the building.

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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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Nick Briggs/Comic Relief
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What Happened to Jamie and Aurelia From Love Actually?
May 26, 2017
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Nick Briggs/Comic Relief

Fans of the romantic-comedy Love Actually recently got a bonus reunion in the form of Red Nose Day Actually, a short charity special that gave audiences a peek at where their favorite characters ended up almost 15 years later.

One of the most improbable pairings from the original film was between Jamie (Colin Firth) and Aurelia (Lúcia Moniz), who fell in love despite almost no shared vocabulary. Jamie is English, and Aurelia is Portuguese, and they know just enough of each other’s native tongues for Jamie to propose and Aurelia to accept.

A decade and a half on, they have both improved their knowledge of each other’s languages—if not perfectly, in Jamie’s case. But apparently, their love is much stronger than his grasp on Portuguese grammar, because they’ve got three bilingual kids and another on the way. (And still enjoy having important romantic moments in the car.)

In 2015, Love Actually script editor Emma Freud revealed via Twitter what happened between Karen and Harry (Emma Thompson and Alan Rickman, who passed away last year). Most of the other couples get happy endings in the short—even if Hugh Grant's character hasn't gotten any better at dancing.

[h/t TV Guide]

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