Circo Massimo (Circus Maximus), is the biggest building for shows of all times, it is 600 metres long and 140 metres wide; it is by the legend connected to the origins of the city: in fact during the games in honour of Conso, the rape of the Sabines happened and hence the birth of life in the city. Actually, a first arrangement of Valle Murcia – Murcia was, according to the tradition, the valley’s tutelary deity – it goes back to the age of the Tarquini and it can be connected to the construction of a sewer which permitted the drainage of the whole area and to regularise the ground. The equipment was probably not enough for this phase, but subsequently, throughout the centuries, there must have been many works in this area and starting with century II BC, also monumental like per the arch of Stertinio erected in 196 BC, the columns with statues, the support with the ova (marbles) in order to easily count the turns.Only Julius Caesar had a real brickwork constructed and its map is kept, at least partially, in the following constructions as witness the many reticulate works in various points during the excavation. Certainly the intervention of Augustus was of great importance: he completed and restored the hippodrome, he decorated it with the obelisk, which is now in piazza del Popolo, and built the pulvinar. Devastated many times by fire and consequently restored, it was then re-constructed almost integrally during the age of Domitian and Traian, phase to which most of the structures in bricks now visible belong. A great number of interventions were made by the following emperors, both structural, as it is proved by the section of brick walls, and finalised to the decoration, often of great importance: exemplar is the erection of the gigantic obelisk brought to Rome by Costante II, now at the Lateran.Like other buildings for shows, the tier of seats divided in three floors rested on parallel and radial structures that defined, on the inside, rooms with different functions. Going from the outside towards the arena, there is the external ambulatory, the barrel vaults, the intermediate ambulatory, another row of rooms adherents to the ima cavea. The barrel vaults have a ternary rhythm: one gave access to the ima cavea, one was dead ended and the third lodged the double flight of stairs that brought to the superior ambulatory which was obtained by internal curves inside the space of the barrel vaults. The two long straight wings of the tier of seats merged in the hemicycle at which centre there were the three barrel vaults in honour of Titus. At the opposite side, disposed on a large curve there were twelve carceres surmounted by the loggia from which the magistrate used to throw the map. The heart of the building was the spine limited at the extremities by the meta triplepointed; it held the ova (marbles) and the dolphins needed to signal which one of the seven turns, foreseen by the race, they were at. It was decorated by columns, statuary groups, altars, small temples and also two obelisks. The spine was, in fact, the best place to welcome the old and new cults of the circus valley, excluding the altar of Conso which was underground by the first mete, the Murcia votive chapel which was in the area of the track close to the cavea and to the temple of the Sun that was inserted in the tier of seats.The circus kept its activity, maybe just partially, until 549 when Totila gave the last games. Afterwards, the area became agricultural while in the hemicycle the deaconry of S. Lucy in Settizodio settled, with a big functioning complex for the assistance needs of the pilgrims, of it there are or could be reconstructed some minor constructions and the small tower. Subsequently, this complex, having become property of St. Gregory, was given in emphyteusis to Frangipane (1145); during the same period (1122) the aqua Mariana was brought to Rome, it ran across the Circus before flowing into the Tiber. A particular use was reserved to the slope of the Aventino, in fact from ‘500 on, it was used as a Cemetery for Jewish people. A new industrial phase was registered at the beginning of ‘800: a gasometer was installed towards S. Maria in Cosmedin and little by little, stores, factories, craftsmen businesses and houses got settled.The release of the area, hoped for by decennials, started with the works for the creation of the Monumental Area during the ‘30s at the same time as great excavation works started which, together with the present ones, have lighted up a good part of the hemicycle and the ruins of Titus’s arch.