Original: Major auto racing events are usually named Grands Prix ( plural form of Grand Prix ) , a tradition dating back to the first decade of the 20th Century and the Grand Prix motor racing of the 1920s and 1930s .
Simplified: Major auto racing events are usually named Grands Prix , a tradition dating back to the first decade of the 20th Century and the Grand Prix motor racing of the 1920s and 1930s .