The Trevi Fountain holds 66,000 gallons of water and rises 86 feet from the façade of Palazzo Poli, but architect Nicola Salvi never saw it finished. He died in 1751, eleven years before completion, though he lived long enough to exact revenge on a neighbourhood barber. The barber's shop overlooked the construction site, and he spent years hectoring Salvi with criticism. Salvi built the Ace of Cups, a large travertine vase on the fountain's balustrade, positioned precisely to block the barber's view forever.

The fountain marks the terminal point of the Aqua Virgo, a Roman aqueduct completed in 19 BC by Marcus Agrippa. According to legend, a virgin girl led Agrippa's thirsty soldiers to the spring eight miles northeast of Rome. The aqueduct's water was once so pure that Augustus recommended it to people complaining about wine shortages. It runs underground for most of its 13-mile route and still functions 2,000 years later, though the water is no longer drinkable.

VoiceMap's self-guided audio tours trace the barber story, explain the panels flanking Neptune that depict the aqueduct's Roman origins, and follow how Agrippa's ancient waterworks still feed the fountain and Rome's other Baroque masterpieces across the historic centre.