Millions of drivers enter highway tunnels every day all over the world. The Mont Blanc tunnel was considered one of the world’s engineering marvels, and although the longest in the world, penetrating under the highest European peak, it was considered one of the safest, until on the 24th of March 1999 something went horribly wrong. When a Belgian truck driver transporting margarine and flour to an Italian food company saw smoke billowing from under the cabin of his truck, he stopped and fled, blocking the tunnel and creating a tail back for five kilometers going back to the French side. The Italian smoke detectors had been turned off after a false alarm the previous day so response was slow. The drivers in the cars and trucks blocked in the tunnel had no idea what was going on until thick black smoke began approaching them fast; then the truck exploded altogether, the margarine turning into the equivalent of 23 thousand liters of gasoline.  The vehicles inside the tunnel caught fire and survivors, including firemen, headed for the fire safety chambers. They were designed to withstand fire for 4 hours but the fire burned for 50, reaching more than 1000°C.