The 80th Indianapolis 500 was held at an automobile racing circuit that was formerly the home of what?
1996 Indianapolis 500: The 80th Indianapolis 500 was held at the Indianapolis Motor Speedway in Speedway, Indiana on Sunday, May 26, 1996. Indianapolis Motor Speedway: The Indianapolis Motor Speedway is an automobile racing circuit located in Speedway, Indiana, (an enclave suburb of Indianapolis) in the United States. Indianapolis Motor Speedway:  It is the home of the Indianapolis 500 and the Brickyard 400, and formerly the home of the United States Grand Prix.
the United States Grand Prix