An archaeological investigation comprising excavation, core sampling, geoelectric and georadar surveys has been undertaken in the western sector of Piazza del Colosseo. The area is centred on the remains of the Meta Sudans and delimited to the south by the Arch of Constantine, to the west by the Palatine and the Temple of Venus and Rome, to the north by the base of Nero's Colossus and to the east by the Flavian Amphitheatre. The complex structural and statigraphic evidence documents the historic and monumental evolution of one of the city's cardinal points, an area where several ancient roads met, creating a hub for four or five of the Augustan regions (II, III, IV, X, I?). The most important evidence, both in terms of the monuments themselves and their role in Imperial symbolism and propaganda, comes from the monumental fountain of the Flavian period known as the Meta Sudans, from its Augustan predecessor and the adjacent sanctuary which had existed from at least the Orientalizing period and was destroyed in the fire of 64A.D. It is possible that this building was the Curiae Veteres and it has yielded a quantity of important architectural, epigraphic and votive material. In this area the urban layout, as far as basic infrastructure such as roads and sewers was concerned, was already established at least as early as the archaic period and grew in density until the Claudian period. At first its streets were cobbled (6th-3rd centuries B.C.) and later paved in basalt (2nd century B.C. onwards). They were lined with buildings with living quarters on the upper floors (in one case with a small bath) and courtyards (one with a portico), shops and services on the ground floor and basement levels. The fire of 64 A.D. and the enormous complex that formed the Domus Aurea radically changed the urban fabric of this area, removing valleys and housing blocks and providing the basis for its subsequent transformation into the piazza which still exists today. This piazza was begun in the Flavian period, completed during the Hadrianic and Constantinian periods and after abandonment during the medieval and modern periods was once more brought to light by the extensive earth removal carried out in the 19th century. (S. Zeggio)