Originally a superspeedway was an oval race track with a length of one mile or more. Since the introduction of the intermediate oval, Superspeedway is an oval race course of 2 miles or longer. There are six active superspeedways in the United States, the most famous being Indianapolis Motor Speedway and Daytona International Speedway, both long. These tracks were built in 1909 and 1959 respectively. Indianapolis Motor Speedway was built as a facility for the automotive industry to conduct research and development. Daytona International Speedway was built as a replacement for the Daytona Beach Road Course, which combined the town's main street and its famous beach. Daytona hosts the Daytona 500, NASCAR's most prestigious race, while the Indianapolis Motor Speedway is home to the Indianapolis 500 and the Brickyard 400.