In September 1940, four teenagers and a dog slid down a dark shaft in the French countryside expecting a tunnel to a ruined manor. Instead they found themselves standing inside a 20,000-year-old art gallery, surrounded by massive animals seemingly stampeding across the limestone ceiling.

This episode explores the Lascaux Cave, a stunning testament to prehistoric genius and a tragic lesson in loving a masterpiece too much. We unpack the sophisticated techniques behind over 6,000 figures, the competing theories about their meaning, and how modern curiosity unleashed a biological disaster that locked the cave away forever. It is a story about imagination, preservation, and what survives us.

• The prehistoric airbrush technique of blowing mineral pigment through hollow bones
• The crossed bison panel that achieved 3D perspective  ...