Monza in 1961 still used its full combined road-and-banking configuration, the steep concrete bankings adding raw speed to a circuit that already ran cars close to 170 miles per hour on the straights. Ferrari arrived dominant, with four cars entered and two drivers — Wolfgang von Trips and Phil Hill, teammates and rivals — separated by a single point at the top of the championship standings. Whoever finished ahead of the other, roughly, would be champion.
The race unravelled almost immediately. On the second lap, approaching the Parabolica, von Trips's Ferrari made contact with Jim Clark's Lotus as Clark attempted to pass. The exact cause was disputed for years afterward — some blamed von Trips moving across the track, others blamed Clark's line — but the outcome was not in question. Von Trips's car was launched sideways, climbed the earth embankment separating the track from the spectator area, and cartwheeled through the crowd standing behind a wire fence that offered no meaningful protection. Von Trips was thrown from the car and killed instantly. Fifteen spectators died with him, and dozens more were injured. It remains the deadliest single accident in the history of the World Championship.
Incredibly, by the standards and information flow of 1961, the race continued. Many spectators elsewhere on the circuit did not learn what had happened until after the chequered flag. Phil Hill, unaware of the scale of the tragedy, kept racing and won — securing enough points to become World Champion, the first American to do so, in a race where his teammate and closest championship rival had just been killed feet away from him.