It is contested as part of the IndyCar Series, the top level of American Championship Car racing, an open-wheel, open-cockpit formula colloquially known as “Indy Car Racing”. The track itself is nicknamed the “Brickyard”, as the racing surface was paved in brick in the fall of 1909. One yard of brick remains exposed at the start/finish line.
The event billed as The Greatest Spectacle in Racing is considered part of the Triple Crown of Motorsport, which comprises three of the most prestigious motorsports events in the world, also including the Monaco Grand Prix (which traditionally falls on the same day as the Indianapolis 500) and the 24 Hours of Le Mans.
The event is steeped in tradition, in pre-race ceremonies, post-race celebrations, and race procedure. The most noteworthy and popular practices are the 33-car field lining up three-wide for a start, the annual singing of “Back Home Again in Indiana,” and the victory lane bottle of milk.
Also unique is that qualifying requires the driver to complete four, rather than one, timed laps and qualifying itself has a separate weekend.
According to en.Wikipedia. Source of photos: internet