Hadrian's Wall: The History and Construction of Ancient Rome's Most Famous Defensive Fortification
"[The Romans], thinking that it might be some help to the allies [Britons], whom they were forced to abandon, constructed a strong stone wall from sea to sea, in a straight line between the towns that had been there built for fear of the enemy, where Severus also had formerly built a rampart." (Bede's description of Hadrian's Wall in the Middle Ages)
The Romans were master builders, and much of what they built has stood the test of time. Throughout their vast empire, they have left grand structures, from the Forum and Pantheon in Rome to the theatres and hippodromes of North Africa and the triumphal gates in Anatolia and France. Wherever they went, the Romans built imposing structures to show their power and ability, and one of their most impressive constructions was built on the northernmost fringe of the empire.
In 55 BCE Julius Caesar was still dealing with Gaul, but that year he also led the first Romans into Britain, accusing tribes there of aiding the Gauls against him. With winter fast approaching, Caesar's forces did not make their way far into the mainland that year. But the following year Caesar's soldiers advanced into the island's interior and conquered a large swath of territory before a revolt in Gaul once again drew him back across the channel. The Romans eventually established enough of a presence to set up the outpost of Londinium, which ultimately morphed into one of the world's most famous cities today - London.