The deadliest day in motor racing history, 70 years ago On This Day. The mighty Mercedes 300SLRs faced off against the Jaguar D-types at the 1955 Le Mans 24 Hours, with Mercedes' Juan Manuel Fangio and Jaguar's Mike Hawthorn smashing lap records while dicing for the lead; their pace was so frenetic that two hours in, they'd lapped all but five cars. Hawthorn, fervent in his desire to beat the German team, lapped Lance Macklin's Austin Healey and pulled back in front of Macklin to dive for his pit box. Macklin braked and swerved, and the oncoming Mercedes of Pierre Levegh ran over his Healey like a ramp, bouncing off the embankment into concrete. The magnesium-bodied car scattered into the crowd and exploded into flames. At least eighty were killed, including Levegh.  After consulting with bosses in Stuttgart, Mercedes later withdrew from the race, asking rivals Jaguar to do likewise; Jaguar declined. Initially distraught, Hawthorn went on to win with co-driver Ivor Bueb, and section...