Located in the valley between the Palatine Hill and Aventine Hill, it was probably built by the Etruscan kings of Rome, and was the site of public games and festivals influenced by the Greeks in the 2nd century BC. Julius Caesar expanded it around 50 BC, after which the track was about 600 metres long and 225 metres wide and could hold 150 000 people. Titus Flavius built the Arch of Titus above the closed end, on the Forum Romanum, and Domitian connected his new palace on the Palatine to the Circus so he could more easily watch the races. Trajan later added another 5000 seats, and expanded the emperor's seating so that he was more visible to the public.
The most important event at the Circus was chariot racing. The track could hold 12 chariots, and the two sides of the track were separated by a median called the spina. Statues of various gods were set up on the spina, and Augustus placed an Egyptian obelisk on it as well. At either end of the spina was a turning post, the meta, around which chariots made dangerous turns. One end of the track extended further back than the other, to allow the chariots to line up to begin the race. Here there were starting gates, carceres, which staggered the chariots so that each travelled the same distance to the first turn.
Very little now remains of the Circus, except for the now grass-covered racing track and the spina. Some of the starting gates remain, but most of the seating has disappeared. The obelisk was removed in the 16th century by Pope Sixtus V and placed in the Piazza del Popolo. In the 19th century the site began to be excavated and partially restored, but there have not yet been any large-scale excavations there.