Some 15,000 years ago, in what is now the Dordogne region of France, someone – man or woman, we don’t know – crawled hundreds of metres through a dark underground passage no more than one metre high. Then he or she scratched a few lines on a bulge of rock. Suddenly, the rock was transformed: an image of a horse appeared. No one else could witness the appearance of the animal: only one person at a time could fit into the confined space. Then he or she retreated back down the passage to the world of light.
A few kilometres away a different scene was enacted. In a large subterranean chamber a number of people gathered to mix paint and to erect scaffolding. Then, with broad sweeps and different colours, they created a procession of horses, aurochs, deer and, hidden amongst them, a solitary bear.