The wall systems the Romans built in Britain get all of the attention, but that era of emperors were building walls all over the place, including a much longer

The wall systems the Romans built in Britain get all of the attention, but that era of emperors were building walls all over the place, including a much longer and more extensive section between the Rhine and Danube[1], and yet more across the other far-flung borders, in every quarter of the empire. [1] https://en.m.wikipedia.org/wiki/Limes_Germanicus https://en.m.wikipedia.org/wiki/Limes_Germanicus