An open-wheel car is a car with the wheels outside the car's main body, and usually having only one seat. Open-wheel cars contrast with street cars, sports cars, stock cars, and touring cars, which have their wheels below the body or inside fenders. Open-wheel cars are built both for road racing and oval track racing. Open-wheel cars licensed for use on public roads, such as the Ariel Atom, are uncommon, as they are often impractical for everyday use.

The Indianapolis 500, formally known as the Indianapolis 500-Mile Race, and commonly called the Indy 500, is an annual automobile race held at Indianapolis Motor Speedway (IMS) in Speedway, Indiana, United States, an enclave suburb of Indianapolis. The event is traditionally held over Memorial Day weekend, usually the last weekend of May. It is contested as part of the IndyCar Series, the top level of American open-wheel car racing, a 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 along with the 24 Hours of Le Mans and the Monaco Grand Prix, with which it typically shares a date.