On September 12, 1940, four teenagers looking for a hole in the ground near Montignac in the Dordogne found a chamber whose walls were covered in painted animals. Marcel Ravidat, Jacques Marsal, Georges Agnel and Simon Coencas had gone back to a spot Ravidat had noticed and where his dog, Robot, had fallen earlier that week. They widened the hole and got in. Then they shone a lamp. The wall was covered in bulls, horses and deer.
Lascaux turned out to be one of the largest and best preserved painted caves in Europe. It holds around 600 paintings and close to 1,500 engravings, in a series of chambers and passages, with the Hall of the Bulls about 20 metres long and containing bulls up to five metres across. The animals are aurochs, horses, red deer, ibex, bison and a few that do not match anything known, and there is one apparent human figure in the shaft. Radiocarbon dating of material from the cave puts the paintings at roughly 17,000 to 21,000 years old, in the Magdalenian period, which makes them a great deal older than the Egyptian tombs and about three times as old as the pyramids.
The discovery happened three months after the German occupation of France and the cave was not opened to the public until 1948, after which it became one of the most visited sites in the country. The Abbé Henri Breuil, who was the leading prehistorian of the period, surveyed it and made the drawings and descriptions that most people worked from for decades.
The problem was the visitors. Their breath did it. Carbon dioxide, water vapour and body heat from tens of thousands of people a year changed the cave's microclimate, and by the late 1950s the paintings had a green algal growth and a white calcite film. Andre Malraux, then minister of culture, closed Lascaux to the public in 1963.
Since then the original has been under climate control and almost nobody goes in. A partial replica, Lascaux II, opened in 1983 a few hundred metres away, and a full replica, Lascaux IV, opened in 2016 as part of a larger centre. The original was inscribed on the UNESCO World Heritage list in 1979, as part of the painted caves of the Vézère valley.