A mosquito-infested and swampy plain lying north of the city walls, Rome's Campus Martius, or Field of Mars, was used for much of the period of the Republic as a military training ground and as a site for celebratory rituals and occasional political assemblies. Initially punctuated with temples vowed by victorious generals, during the imperial era it became filled with extraordinary baths, theatres, porticoes, aqueducts, and other structures - many...