The Mont Blanc Tunnel that connects Chamonix, Haute-Savoie, France with Courmayeur, Aosta Valley, Italy, via European route E25 through the Alps, was the scene of a fatal fire that took the lives of 38 people on this day in 1999. A cargo truck carrying flour and margarine caught fire while passing through the tunnel and when the driver stopped his truck to try and extinguish the flames he was quickly overwhelmed by the heat.
Authorities stopped additional traffic from entering the vehicle once the emergency was reported, but as many as 10 personal vehicles and 18 trucks were stuck inside. The toxic fumes prevented people from escaping and the intense heat melted wiring, turning the tunnel into a dark, smoke-filled void that made fighting the flames nearly impossible. The fire burned for more than 53 hours. Numerous improvements were made to the tunnel in the years following to prevent such a disaster from occurring again. The resulting manslaughter trial found 13 defendants to be guilty of various charges, including the driver of the truck that caught fire.