The 1955 Milli Miglia, of course.
His record of 10h7’48” still stands to this day, and will never be beaten. Why? Because the Mille Miglia was absolutely insane. Imagine around 500 cars on public roads going over 200 km/h through cities and villages. Oh, and those roads were NOT closed to the public.
And some say that the Avusrennen was bonkers…