The ancient Romans used aqueducts to carry water from distant springs into central Rome. As the empire decayed, so too did these ambitious public works. When Rome experienced a renaissance—not to mention a population boom—in the modern age, popes took cues from the emperors before them and repaired these ancient water channels. To celebrate their grand projects, they built massive public fountains like the Fontana dell'Acqua Paola on Janiculum Hill. Dubbed er fontanone ("the big fountain"), this 17th-century structure was commissioned by Pope Paul V to commemorate the repair of the Traiana aqueduct that tapped a spring near Lake Bracciano north of Rome.