And so a few days later, he returned with some rope and three friends—sixteen-year-old Georges Agniel, fifteen-year-old Jacques Marsal, and thirteen-year-old Simon Coencas. Georges was on summer vacation and would soon return to Paris for the school year. Jacques, like Marcel, was a local. And Simon, who was Jewish, had sought refuge with his family in the countryside amid the Nazi occupation of France.

That day, Agniel later remembered, “We descended with our oil lamps and went forward. There were no obstacles. We went through a room and then by the end we found ourselves in front of a wall and saw that it was full of drawings. We immediately understood we were in a prehistoric cave.”

Simon Coencas recalled, “With my little gang . . . we were hoping to find a treasure. We found one, but not the one we thought.”

In the cave, they discovered over nine hundred paintings of animals—horses, stags, bison, and also species that are now extinct, including a woolly rhinoceros. The paintings were astonishingly detailed and vivid, with red, yellow, and black paint made from pulverized minerals that were likely blown through a narrow tube—possibly a hollowed bone—onto the walls of the cave. It would eventually be established that these artworks were at least seventeen thousand years old. One of the boys recalled that in the flickering of their oil lamps, the figures seemed to be moving, and indeed, there is some evidence that the artists’ drawing techniques were intended to convey a kind of flip-book animation by torchlight.*

Just days after the cave’s discovery, Simon Coencas and his family, fearing the growing Nazi presence in the countryside, moved again—this time to Paris, where relatives had promised to help hide them. But the family was betrayed by a business partner, and Simon’s parents were murdered by the Nazis. Simon was imprisoned for a time, but narrowly escaped the death camps and survived the rest of the war hiding in a tiny attic room with his siblings. He would not see his three friends from that Lascaux summer for forty-six years.

So there were four boys who discovered the cave, but only two who could remain there—Jacques and Marcel. They were both so profoundly moved by the paintings that all through that fall and winter, they camped outside the cave to protect it. They only left after a reinforced door was installed at the cave’s entrance. In 1942, Jacques and Marcel joined the French Resistance together. Jacques was captured and sent to a prison camp, but both survived the war, and when they got home, they both immediately returned to the cave.

After World War II, the French government took ownership of the site, and the cave was opened to the public in 1948. Marcel and Jacques both served as tour guides. When Pablo Picasso saw the cave paintings on a visit that year, he reportedly said, “We have invented nothing.”

The cave is not particularly large—only about ninety meters deep—but it contains nearly two thousand paintings. Aside from the animals, hundreds of abstract shapes are painted on the walls, most commonly red and black circles.