Interesting article at drf.com by Alan Shuback on whether the Prix de l'Arc de Triomphe is the world's best race.

Using the admittedly subjective criteria of the lifetime Group 1 or Grade 1 victories of the first three finishers of the four aforementioned races since 1996, we find that the Arc comes out on top. During that period, the Arc's first three finishers have won a total of 95 Group 1 races. That comes to an average of 3.17 Group 1 scores for each of them. By comparison, the first three finishers in Leopardstown's Irish Champion Stakes over the same period have each won an average of 2.83 Group 1 races. The figure for Ascot's King George is 2.67, while the Breeders' Cup Classic checks in at 2.47.