A large building in Roman antiquity, generally a long oblong or oval, used for horse and chariot racing and public spectacles. The audience sat in rising tiers of seats around the track and the races were run around a central island. Rome's Circus Maximus, the largest and best-known, was originally built by Tarquinius Priscus, but enlarged various times until late Roman period. It is essentially a Roman development from the Greek stadium or hippodrome.