Database: Acqua Marcia

This impressive system was the longest of the 11 Roman aqueducts, running a staggering 91 miles. Built between 144-140 B.C.E., the aqueduct was named for its creator, praetor Qunitus Marcius Rex.

It was maintained and even expanded for the better part of 200 years, but, typical of any free public service, by Nero's reign so many people siphoned water out of it for personal use the flow was barely a trickle by the time it arrived in the city.