6. Pierre Levegh’s 1955 Mercedes 300 SLR
Number of deaths: 83 officially (though some accounts put the total closer to 130)
A combination of historically unfortunate circumstances and an ill-thought out engineering decision resulted in over 80 fatalities (though some sources indicate the total was quite a bit higher) in the 1955 running of the 24 Hours of LeMans. Levegh hit the rear of a competitor’s car at just the right angle to launch him into the air and straight into the crowd at around 150 mph. Much of the car broke apart on impact, doing things far too graphic to recount here.
Making matters worse, the car’s skin was made largely of magnesium, which promptly caught fire and continued sparking for hours. As a direct result of the tragedy, Mercedes pulled out of factory-sponsored racing for decades, and Switzerland banned motorsport. To date, this is the single worst incident in motorsport history.