Aqua Marcia

The Aqua Marcia is the third oldest and longest of ancient Rome's major aqueducts, stretching roughly 91 kilometers and constructed between 144 and 140 BC under praetor Quintus Marcius Rex. Its water was considered the purest and coldest in Rome, and the aqueduct was deliberately built on the tallest arches in the city to supply the Aventine and Capitoline hills — a feat of hydraulic engineering that drew admiration even in antiquity. Restored multiple times, including by Augustus and Caracalla, portions of the system still feed Rome's water supply today. The surviving arch remnants near Gabii, protected as an Italian national monument, give a direct sense of Roman construction technique in tuff and opus incertum masonry.