Chauvet's cave was sealed with an iron door soon after it was found in 1994.
Cave of Forgotten Dreams, a new documentary by Werner Herzog, is a striking and characterful work of art, framing another that is wholly extraordinary. In 1994 three experienced French speleologists, exploring the limestone gorges of the river Ardèche, crawled their way into a large cave system in which Palaeolithic imagery swung into view. Jean-Marie Chauvet, the team’s leader, has described how they were immediately awestruck by the “remarkable realism” and “aesthetic mastery” of the countless animal depictions that sprang out as their torch-beams roved the cave walls. But conscious that cave paintings such as those at Lascaux, discovered in 1940, had soon become infested with the mold carried on visitors’ breaths, Chauvet and his colleagues notified the regional authorities, and within a month, before publicly announcing the discovery, a steel door was installed to seal off the opening in the rock-face. Only the scientifically qualified might pass inside, and those in very small numbers, confining their footsteps to a narrow raised walkway.
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Radiocarbon analyses indicate that charcoal used by painters at Chauvet comes from pines that were alive some 32,000 years ago. It follows that these are easily the world’s oldest known paintings. Long before the eighteenth millennium BCE—the date assigned to Lascaux—a rock-fall had closed off Chauvet’s original entrance, stopping all further incursion into the cave and preserving the imagery within in pristine condition. The only figurative artifacts that we know to predate Chauvet are some slightly older carvings in stone and mammoth ivory dug up from cave floors in Swabia (in southern Germany) and Austria. Herzog brings these sculptures into his film, along with some flutes carved from bone found at the same sites. Looking at these remains, so it strikes him, we are looking at the very roots of art and of music. “It is as if,” he at one point muses, “the human soul had awakened here.”
http://www.nybooks.com/blogs/nyrblog/2011/may/04/werner-herzog-cave-forgotten-dreams/