The many Roman walls still visible today throughout Europe and the Mediterranean, be they defensive walls such as the Servian Wall or house and monument walls, tell us a great deal about the evolution of Roman construction techniques. Roman walls went from dry-stone and sun-dried bricks walls at the beginning of Roman civilization to walls built with a concrete core and brick facing by the beginning of the Empire. These walls also provide many clues to the history of ancient Rome and the different stages of the Roman economy and society.
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/942/roman-walls/.