Imperial Roman army other military facilities e.g. Hadrian's Wall itself was built by the army. But they also built up much of a province's Roman infrastructure: trunk Roman roads, bridges, docks, canals, aqueducts, entire new cities such as "coloniae" for veteran legionaries, public buildings (e.g. basilicas and amphitheatres). The army also carried out large-scale projects to increase the land available for agriculture, such as forest clearance and draining marshes (e.g. the large-scale drainage of the Fens in eastern England, which were probably developed as a huge imperial estate). The army also excavated many of the mines and quarries that produced the raw materials
City Wall and Moat wooden towers. Attackers had to construct bridges from their wooden towers in order to reach the top of the wall, thus exposing themselves to the defenders of the city. Archaeologists have not been able to provide a precise date for the construction of the city wall and its moat, although historical chronicles suggest the 9th century. Both wall and moat were built atop the Phoenician cemetery, and cut across the ruins of the Phoenico-Persian, Hellenistic and Roman residences. In the late 19th century, the city wall and its moat lost their strategic significance. By the early 1900s, the wall had