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
Vestiges of the Gallo-Roman wall, Grenoble to the construction of the wall in the end of the 3rd century AD, the Gallic city of Cularo (Grenoble) was surrounded by a fence and a ditch. During the Roman Peace (Pax Romana) period (27 BC to 180 AD), the walls were not guarded. In the 3rd century, the city was weakened by the invasion of barbarians, so the Gallo-Romans built a surrounding wall, under the rule of the Emperor Diocletian. The wall surrounding Cularo covered 9 hectares of land and had two main gates. At the time, the city had an approximate population of 2000 inhabitants. Cularo appears