It began as a glamorous clash of automotive titans at the 24 Hours of Le Mans. By sunset on June 11, 1955, it had become the deadliest day in the history of motorsport, with over 80 dead and a disaster that rewrote racing safety worldwide.

This episode traces how a lethal gap between explosive technological progress and antiquated infrastructure turned a 170 mph race onto a track built for 60 mph cars into catastrophe. We follow the rivalry between Mercedes, Jaguar, and Ferrari, the chain-reaction crash, the chemical fire, the controversial decision to keep racing, and the decades-long bans that followed.

• How a 1923-era track, a four-foot earthen bank, and no seatbelts set the stage for mass casualties
• Why Jaguar's advanced disc brakes paradoxically triggered the collision that launched Pierre Levegh's Mercedes into the c ...