The Indianapolis 500 was designated a Grand Épreuve along with one of the oldest motor races in what?
1924 Grand Prix season:  The Indianapolis 500 was again designated a Grand Épreuve by the International Sporting Commission of the AIACR, along with the French Grand Prix, held in Lyon and the Italian Grand Prix at Monza. French Grand Prix:  It is one of the oldest motor races in the world.
i don't know