Chapter 1

Pygmalion's Spectacles

There is a unicorn in a cavern under an ancient forest in France. I've seen it myself, even though it wasn't really there; I've stood in front of it, even though its home is a place where no one can go.

The unicorn is painted on the wall of Lascaux Cave, a subterranean complex in the VŽzre Valley, about two hours' drive east of Bordeaux. Seventeen thousand years ago, some of the first modern humans in Europe decorated the caverns with hundreds of images of animals, symbols, and abstract shapes. In 1940, it was rediscovered by a group of teenagers and became one of the most famous archaeological sites in the world.

For decades following the discovery, countless tourists flocked to Lascaux. Henri Breuil, a French priest and archaeologist who was one of the first researchers to study the caves, called it the Sistine Chapel of prehistory; after artist Pablo Picasso saw the paintings, he lamented that his entire generation of revolutionary artists had "invented nothing new." But the ancient drawings were fragile, and the presence of so many visitors took a toll. In 1963, the French government banned the public and locked the doors.

Fortunately, technology allows a modern tourist to sneak inside. Lascaux comes to life in 360-degree videos and virtual reality tours; I'd seen photos of the caves and studied their paintings in college, but it took seeing that unicorn in VR to really understand the place. Even though the French government has built detailed replicas of the caves for people to visit, the virtual version makes for a better trip-it's appropriately claustrophobic and free from the distracting presence of other tourists.

It's also a particularly fitting way to visit, because Lascaux may be the oldest example in human history of an attempt to create a virtual world. You'd never know it from looking at photographs, but when you stand inside the caves-virtually or in person-the intention is clear. Just like VR headsets block the real world from view, the caverns separate a visitor from the forest above. Instead of drawing with pixels on a screen, the cave artists used pigment on rock walls. Lascaux's creators used the topography of the caverns to create immersion: a chamber decorated with sketches of wild horses isn't just a jumble of drawings, but a herd that surrounds the viewer. They used perspective tricks to make the illustrations seem three-dimensional: the body of an ox is presented in profile, but its head is turned to face the viewer. And they used the shape of the rock to give their art depth and shape; for example, a twist in a wall makes a deer appear to turn away as it dashes around a corner.

No one knows why the people who created the caves went to so much trouble. Perhaps the goal was to enthrall the viewer in order to teach them something, like an Upper Paleolithic version of a flashy how-to video on YouTube: As writer and technology expert Howard Rheingold suggests, "subterranean cyberspaces" like Lascaux may have served to "imprint information on the minds of the first technologists." Or maybe the caves were immersive entertainment, an attempt to tell a story in the most realistic way possible, to convey the excitement of hunting without the risk of getting gored or trampled.

In the millennia after the cavemen left their caves, increasingly advanced civilizations created increasingly sophisticated immersive entertainment. Around 2,500 years ago, the ancient Greeks built their own VR viewers out of wood, stone, and marble-the word theater comes from the Greek verb...