From 2005 to 2012 the Universities of Granada and Barcelona excavated a domus, while from 2013 Florida State University has excavated a bath building in the southwest corner of the Forum. From 2016, l’Università di Firenze has been excavating along the processional street P. City walls and gates The city wall of Cosa was built at the time of the foundation of the colony on 273 BCE. It is 1.5 kilometres (0.93 miles) long and built in polygonal masonry of Lugli's third type. It included a system of interval towers, numbering eighteen in all. These are found at irregular intervals, and all but one are rectangular in plan - the exception is round. There are three gates which correspond to as many roads: the northwest, or Florentine gate, which corresponds to the modern entrance to the site, the northeast, or Roman gate, and the southeast, or maritime gate. These each have the same structure, twin gate, one in line with the walls and one to the inside, with a space between them. The arx also had an independent circuit wall. At the western corner of this was a postern, closed in the early Byzantine period, when the hill was refortified with a wall built with an emplecton. A final, medieval, circuit in mortared rubble masonry runs along the same line. In recent years the Archaeological Soprintendenza of Tuscany has conducted extensive documentation, repairs and reconstructions of the walls. Urban layout Within the city walls the urban area was divided into an orthogonal plan, with space allotted for civic, sacred, and private architecture. The plan represents a subtle adaptation of an orthogonal plan to the complicated topography of the hill. The forum was found on a saddle between two heights, with the sacred area, with the Capitolium, linked to it by a broad street. Recent excavations have suggested that the original layout provided for about 248 houses, of which 20 were intended for the decurions, and were double the size of the houses of the ordinary citizens. The larger houses were found on the forum and the main processional streets. Temples on the Arx The vast majority of religious monuments at Cosa were located at the Arx, "an area sacra, abode of those gods, quorum maxime in tutela civitas." The Arx was positioned at the highest and southernmost point of the colony. Its limits were defined by the Town Wall on