France’s historic Lascaux cave has long been closed to the public in order to protect the stunning prehistoric artwork hidden within its 18,000-year old walls. December 10th marked the unveiling of a €66 million ($94 million) full-scale replica of the site.

Dubbed Lascaux 4, the project is is the most complete recreation of the cave to date, reconstructing the entirety of one the most significant archaeological discoveries of the 20th century.

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“This is more than a copy, it’s a work of art!” said French President François Hollande while touring the new facility, according to Agence France Presse.

French President Francois Hollande visits Lascaux 4, a new replica of the prehistoric paintings of the Lascaux cave, in Montignac, on December 10, 2016. Regis Duvignau/AFP/Getty Images.

Four young boys exploring Lascaux Hill found the caves in 1940. “With my pals, we climbed down to explore a hole, we advanced bit by bit and at some point we came up upon the chamber of the bulls,” Simon Coencas, now age 89, told AFP of his discovery of the richly painted cave walls. “We were hoping to find a treasure.” As the last surviving member of the original exploration, he was a special guest at the unveiling of the new replica.

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Following the end of World War II, the site quickly became a popular tourist attraction, but had to be closed to the public in 1963, because visitors’ increased carbon dioxide levels was damaging the ancient artworks. Lascaux has been a UNESCO World Heritage Site since 1979.

French President Francois Hollande visits Lascaux 4, a new replica of the prehistoric paintings of the Lascaux cave, in Montignac, on December 10, 2016. Regis Duvignau/AFP/Getty Images.

Lascaux 4 took four years to complete. (Lascaux 2, completed in 1983, reproduced only 90 percent of the wall art, while Lascaux 3 is selection of highlights from the caves featured in a travelling exhibition.) The new facility opens to the public on December 15, and is expected to attract 400,000 annual visitors.