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CG94 photos

8 Underground Rivers

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CG94 photos

Rivers run underground all over the world. These occur naturally in cave systems, and have been known since antiquity, as evidenced in legendary myths of underground waterways such as the River Styx which forms the boundary between Earth and Hades. But this is about subterranean rivers that were once open to the sunlight and were buried by human hands (or heavy machinery). This happens when cities are built overtop, when wetlands are drained, and when existing waterways are consolidated and hidden to give people and their infrastructures more room to grow or move. In some of those places, people don't even realize there's a river running underneath their homes.  

1. The Tank Stream in Sydney

Photograph by Wikipedia user Shermozle.

When Europeans landed in southern Australia in 1788, they looked for a place with fresh water to settle into. That place was later to be called Sydney. The river that supplied fresh water was diverted into holding tanks by the convicts who were sent there, and so became known as the Tank Stream. With more and more people using it, the stream became polluted and the swamp that was its source was drained in 1850. The remaining stream was covered with stone in 1860, and became part of the city's storm drain system and flows, as it always did, into Sydney Cove.  

2. Neglinnaya in Moscow

Photograph by Wikipedia user A.Savin.

At one point in its history, the Neglinnaya River was used as a moat around the Kremlin. The river flowed through the heart of Moscow, but it impeded construction because of frequent floods. Muscovites built dams, ponds, and mills along the river route for industrial use, leading to pollution of the river. The Neglinnaya was diverted into a parallel canal in 1792 to control flooding, and the old river bed was filled in. The canal then became the carrier of industrial pollution. In 1817, the canal was covered with a vault, creating the Neglinnaya Tunnel, and the river that flowed through it became part of the city's sewer system. Still, it flooded and overflowed into city streets. Several projects since that time have added tunnels to drain excess water from the buried Neglinnaya to control its flow into the Moskva River, shown above. See pictures of those tunnels taken by brave urban explorers.

3. Minetta Brook in New York City

Minetta Brook is one of many waterways that have been paved over in New York City. The freshwater streams that allowed so many people to move into the area eventually became polluted and were incorporated into the city's underground sewers and drainage systems. The Minetta once flowed through Manhattan, providing fresh water to Greenwich Village when it was a farming community in the 1700s. In 2010, urban explorer Steve Duncan traced its route under the city, through passageways only a few feet wide in places. He found it has been "rediscovered" during occasional building projects when water flowed through basements. Tracing the course of the city's storm drains and sewers, Duncan found that the drains were in many places laid out to take advantage of the natural flow of the Minetta.   

4. The Bièvre in Paris

Photograph by Flickr user CG94 photos.

The River Bièvre flows along on the surface from its source near Versailles toward Paris. The diversion of its waters for various projects through history shrunk it to a small stream closer to Paris. Once reaching the city, however, the Bièvre disappears underground, and along its course is diverted into the city sewers. It was covered over due to industrial pollution that began in the Middle Ages. The river once flowed into the Seine within the city, but is now diverted into the main sewer, which is treated and the water released further downriver into the Seine. A restoration project was begun to open the Bièvre in places along its historic route, but a decade later they still don't have the necessary funds. Walking tours are offered of the river's current and historic routes.

5. The Senne in Brussels

The Senne was one of the main waterways in Brussels, Belgium, until the 19th century, but the quirky river was unpredictable and often overflowed its banks. The Senne, like other city rivers, became polluted with industrial and household waste and was gradually replaced by canals for fresh water supplies, which in turn exacerbated the pollution of the river. The downtown area of the river was covered over in a project that ran from 1865 to 1871, and buildings were erected overtop the buried river. The remainder of the river was covered in the 1930s. The underground waterway itself was then diverted, and the former water tunnels were converted to use by the Brussels subway system in 1976. It took until 2007 for the Senne's waters to be treated by modern sewage plants.

6. The River Fleet in London

Photograph by Flickr user diamond geezer.

The best known buried river is probably the River Fleet in London, England. The Fleet flows from a couple of springs in Hempstead Heath through the city into the Thames. The photograph above shows the source pond that feeds into the Fleet. Over the centuries, the river became an industrial sewer as the city grew. Engineers began building over the river in sections in the 1730s, gradually enclosing it in bricks and concrete. The spot where the river emerged after the first section enclosed the river became Fleet Street.

In the 1860s, the lower sections of the Fleet were covered over and it was formally incorporated into London's sewer system.

Photograph by Flickr user

Geographers have recreated maps of the Fleet so its existence might not be forgotten. Urban explorers venture down into the tunnels, but that's tricky, as the Fleet is still a tidal river and the lower tunnels fill to the top during high tide. See more pictures that trace the location of the buried river. The Fleet is far from the only river buried in London. In addition to the many visible tributaries of the Thames, there are dozens that now flow underground, such as the Tyburn, the Effra, the Walbrook, and the Earl’s Sluice, most of which were incorporated into the sewer system just like the Fleet.  

7. ChangPu River in Beijing

Photograph by Flickr user whirlpics.

The burial of natural rivers is often considered a shame in modern times. There are drives to restore many of the world's lost rivers, and some of those projects have yielded spectacular results. ChangPu River was a stream that flowed through the Imperial City, the outer part of the Forbidden City in Beijing. In the 1960s it was covered over and the area became a warehouse district. A restoration project was begun in 2002, and the historic river was uncovered and became the focal point of ChangPu River Park, a small but exquisitely maintained showplace in the heart of Beijing.  

8. The Cheonggyecheon in Seoul

Photograph by Flickr user Seong J Yang.

The Cheonggyecheon was once the main river through Seoul, Korea. It succumbed to the same pressures as other freshwater courses through growing cities, in that it became polluted and was buried and made into a drain. In the 1950s, a freeway was built over the river. In 2001, a group of people approached Dr. Kee Yeon Hwang about restoring the river. Dr. Hwang conducted a feasibility study and found that dismantling the highway, which had been built by a construction company he himself headed, would actually improve traffic flow through the city. With the approval of Seoul's new mayor Lee Myung-bak (who is now the president of South Korea), the restoration project went into high gear in 2003. Now, the river is exposed again, as part of a 3.6 mile park running through the middle of Seoul.  

These are just a few of the many urban rivers that have been confined to underground for many of the same reasons. Each has its own history, and each has many pros and cons to be considered before deciding whether it can be restored to its previous condition.

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iStock // Ekaterina Minaeva
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
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]