The 1955 Le Mans disaster has been considered one of the most horrific crashes in the history of motor racing. The on-track crash resulted in the deaths of 83 spectators along with injuring almost 180 others and the death of Mercedes-Benz race car driver Pierre Bouillin (who went by the name Pierre Levegh).

During the 1955 24 Hours of Le Mans, a series of cars maneuvering around an Austin-Healey driven by Lance Macklin who was slowing to make a pit stop resulted in the Mercedes-Benz driven by Pierre Bouillin hit Macklin from behind and sending Bouillin through the air with part of his car moving past an earthen mound and into the spectator area. Bouillin was killed instantly.

The disaster led to an immediate temporary ban on motor sports in countries such as France, Spain, Switzerland, Germany, and others, until the racetracks could be brought to a higher safety standard. This incident prompted Mercedes-Benz to withdraw from all forms of motor sport until 1989.

More Info: en.wikipedia.org