On 12 September 1940, four boys from the village of Montignac in south-west France squeezed through a fox's den into the dark. Marcel Ravidat went first, and they found themselves among animals: horses, stags, aurochs, ibex and bison, painted on the walls some 21,000 years ago. There are around 600 of them, and horses outnumber all the rest. They were painted by firelight, in ochres and blacks, by people who had watched these animals for a lifetime. What they caught is the hardest thing to show: movement. A head lifts. Legs stretch into a gallop. A herd seems to flow across the rock. For me, this is what makes the painters of Lascaux true artists. They did not copy animals – they caught them in motion. My animals bring that herd back into a room where you can stand beside it. Each horse and bull is shaped by hand in papier-mâché and spun cotton and coloured in the cave's own palette – ochre, umber, charcoal and chalk white – with strong contrast between light and dark. Some gallop, some walk; set together, they move as one.