The world's largest art museum may be more than 200 years old, but its iconic entrance — a glass pyramid — didn't arrive until 1989. To mark the structure's 30th anniversary, street artist JR was commissioned to design an optical illusion made of paper strips. The temporary collage, when viewed from above, gives the famed 21-meter-high (nearly 70-foot-high) pyramid dizzying added depth.

Street artist JR — dubbed the "French Banksy" after the British artist famous for his social commentary — promised his latest work would reveal "the Secret of the Great Pyramid." The installation was created using a technique that distorts the image of the subject unless viewed from a specific angle but he was not able to achieve the project alone.

Some 400 volunteers were roped in to work on the project. They spent four days in teams of 50 to paste strips of printed paper on the cobbles of the courtyard in front of the museum. "There are more than 2,000 strips to paste on the ground, each 10 meters long, so it's a huge puzzle," the artist told the Agence France-Presse news agency.

When finished, the collage became a giant screen that projected the pyramid, apparently emerging from its foundations, as if from a giant quarry of white rock. The ariel view of the image was then projected to the public by two plasma screens in the courtyard. Although the main pyramid was untouched, three smaller pyramids were covered with paper to enhance the final optical illusion.

Despite the hype, some museum-goers were unimpressed, complaining that they couldn't see any optical illusion at ground level. Some even accused the museum that contains the Mona Lisa and Venus de Milo of elitism, because a special VIP pass was the only way to view the installation from a balcony.

The crater collage is the second installation by JR — whose real name is Jean Rene — at the Louvre's iconic pyramid. In 2016, he made the glass structure "disappear" with a black and white photo trick. The nearly 700 glass segments were papered with small portions of images of the Louvre Palace, which the pyramid partially blocks.

Commissioned by the late French President Francois Mitterrand in 1984, the pyramid was hated by many Parisians who said the glass structure was incompatible with the classic French Renaissance style of the Louvre Palace. Chinese-American architect I. M. Pei was also mocked, as he was deemed not French enough. Today, the structure is one of Paris' main landmarks.