Lascaux Caves
The Lascaux caves, discovered by a French adolescent and his young companions in the 1940s, include around 600 drawings of animals from the Upper Palaeolithic period. The murals that cover the cave's walls and ceilings are thought to be around 17,000 years old, the result of a multigenerational art effort.
After World War II, Lascaux opened to the public, but as visitor numbers increased to roughly 1500 per day, the massive volumes of carbon dioxide produced by human breath began to destroy the art. As a result, the original Lascaux cave closed in 1963 and is now only accessible to an ever-shrinking handful of scientists and field specialists each year. Visitors are instead encouraged to visit the neighboring facsimile of the caverns, which has been meticulously rebuilt. Several times a day, professional guides will accompany groups of tourists, offering tours and answering questions about the cave's oddities.
Location: Montignac, France