The centre of the Roman chariot races.

It was used for chariot races and according to the inscription, it was later adapted to serve as a venue for naval games.

It has a rectangular shape and is divided in two lengthwise down the middle along the raised central platform, which would originally have been covered in marble. Still visible are the arena where the races took place, the seating areas or stands, and the doors known as carceres through which the competitors entered the ring. It is one of the best conserved circuses in existence.