For a few precious hours outside the Louvre, the ground around the iconic Pyramid appeared to be in the process of excavation, revealing a hidden portion of the structure. Rendered on paper in black and white, “The Secret of the Great Pyramid” is the second optical illusion involving the Louvre Pyramid by French artist Jeane Rene (better known as JR), and it took a team of 400 volunteers and 2,000 segments of paper to create.

Celebrating the 30th anniversary of the Louvre Pyramid’s creation on March 30th, 1989, “The Secret of the Great Pyramid” stretches to fill the entire courtyard outside of the 12th century museum.

Sadly, it didn’t last. Visitors demonstrated why we can’t have nice things when they tore up the installation within hours of its completion, and now there’s nothing left of it but a few scraps blowing in the wind. But that was all part of JR’s plan. The artist knew the piece was ephemeral, and that being made of paper meant it had a very limited life span. Before its installation, he predicted that some people would destroy the piece unintentionally with their feet, while others would rip pieces away to take home.

“Once pasted, the art piece lives on its own,” he writes. “The sun dries the light glue and with every step, people tear pieces of the fragile paper. The process is all about participation of volunteers, visitors, and souvenir catchers. This project is also about presence and absence, about reality and memories, about impermanence.”

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A post shared by Baptiste (@dessinateurs)

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A post shared by Gjin Pervathi??? (@gjinpervathi)

But for a moment in time, this massive optical illusion was certainly epic, and thankfully, plenty of people caught it on camera while it was still intact. Previously, JR made the pyramid “disappear” in a work of large-scale urban camouflage.

JR is known for his black and white photographic public art installations, typically tailored to the environment in which they’re placed. Sometimes that means placing the leaping figures of Olympic athletes atop buildings in Brazil or taking portraits of the elders of a community and making them impossible to ignore; sometimes it means making overt political statements like a bi-national meal at the United States-Mexico border or towering an image of a Mexican toddler over the border wall for guards to contemplate.

An optical illusion mural affixed to the facade of a medieval fortress in France is no less controversial for its temporary nature, even though the piece is not quite what it seems at first glance. Those aren’t swaths of paint defacing the UNESCO World Heritage Site in Carcassonne, Southern France – they’re ribbons of thin aluminum, which can be easily removed when the installation is taken down in September.

‘Concentric Eccentric’ by Felice Varini continues the artist’s tradition of creating large-scale perspectival pieces in urban environments, and it’s all the more stunning for the contrast it creates.

Fifteen yellow circles radiate out from the entrance to the fortress, drawing in the many tourists who flock to Carcassonne for its picturesque scenery and wine. The installation celebrates the 20-year anniversary of the monument’s UNESCO designation. While the design echoes much of Varini’s past work, it also complements the design of the fortress itself, which consists of two concentric outer walls, 53 towers and barbicans (fortified entrances) to prevent attacks during sieges, the first known use of the technique.

While some might find ’Concentric Eccentric’ a fun addition to the ancient city, some locals weren’t exactly thrilled, calling for the removal of the “filthy” artwork. Some even cried that the work was “ruining our lives.” Some said they welcomed the controversy because it proves that they’re “deeply attached to their heritage.”

To create the mural, local art students projected the circles onto the stone surfaces at night and applied the aluminum strips. France’s Centre Des Monuments Nationaux gives us a look at how this process was carried out in a series of behind-the-scenes photographs viewable on its website.

Photos by André Morin

A wall could look as flat as flat gets until street artist Peeta gets his hands on it with a can of spray paint, distorting its surface, confusing its perspective with three-dimensional illusions. Sometimes, the effect is so convincing, you can’t tell which windows are real and which ones are painted, or whether some elements of the composition really are popping out beyond the wall. Hint: if you think they are, like in the case of the windows on the green-roofed building below, you’re probably wrong.

Peeta – real name Manuel Di Rita, a resident of Venice, Italy who’s been painting graffiti since 1993 – has really upped his game over the last few years. A member of Padova-based EAD crew and New York City-based FX and RWK crews, Peeta also works on canvas and with actual 3D sculpture in PVC, bronze, acrylic resin and fiberglass. His experience with sculptural media really shows in his newest murals, which take the familiar forms of letter-based street art and manipulate them into abstract creations.

“Today, through my anamorphic works I redesign the volumes of any kind of surface involved, thus causing with my paintings a temporary interruption of normality by altering the perception of familiar contexts and so raising a different understanding of spaces, and consequently, of reality as a whole,” says Peeta.

“Metaphorically, I want to neutralize preconceptions and urging the emergence of new perspectives. Anamorphism totally embodies the intent, always pivotal in my production, to reveal the deceptiveness of human perception, the fallacy of narrow and fixed points of view through visual tricks which, proceeding from the attempt to confer a three-dimensional semblance on a pictorial representation, ultimately reveal their will to deceive.”

Peeta’s works have popped up – literally – all over the world, from China to Oregon to Barcelona. Give him a follow on Instagram @peeta_ead to keep up with his anamorphic works and occasionally get some interesting backstory on particular pieces.

Looking at this picture, it seems pretty obvious that something is seriously wrong with the floor… right? And yet, as we should all know by now, things aren’t always as they seem, no matter how hard our brains try to reconcile the fact that a flat surface can look so believably sunken on one side. It’s kind of hard to wrap your mind around the fact that the effect is achieved simply by warping the shape of the tiles as they’re applied to the floor.

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Casa Ceramica Tile Company created the illusion for the entrance to their own showroom in Manchester, UK. People must have had a hard time believing that the tiles are really flat from initial photos posted to Instagram and Twitter, because the company posted subsequent photos and videos of the installation process, saying “Like our entrance floor made from tiles #sorrynotsorry.”

They are actual tiles pic.twitter.com/7HvTqz9jHP

— Casa Ceramica (@casaceramica) September 22, 2017

Apparently, the illusion only works from one direction, and when visitors are exiting the building, it looks like a normal tile walkway.

Here’s how to navigate our floor! #tiles #Manchester #Lovetiles #Illusion #Aliceinwonderland #CharlieAndthechocolatefactory pic.twitter.com/fn8kV2Wcz9

— Casa Ceramica (@casaceramica) September 22, 2017

Unsurprisingly, the illusion blew up on Twitter and became something of an internet sensation. You might dig through the company’s website or Instagram hoping for more optical illusions, but it looks like most of their work is pretty standard. Maybe this project will get them some fun commissions.

Subway cars in Taipei have become swimming pools, basketball courts, baseball fields and track lanes to get residents amped for the upcoming 2017 Summer Universiade, an international multi-sport event for university athletes. While the installations mostly consist of photorealistic photographic murals stuck onto the floors, the illusion comes together pretty nicely, especially in the case of the swimming pool, which matches the existing subway car chairs and poles.

These ‘moving sporting venues’ will transport lots of tourists attending the events, and the city hopes to add to their excitement. The Universiade is the second-largest international sporting event after the Olympics, set to begin on August 19th and end on August 30th, and will include competitions in 22 different sports across 70 venues.

Images by: Taipei City Government Department of Information and Tourism, @skywu0326, @chi._.851229, @nikoleko1007