Ancient Rome’s fresh water was supplied via a series of magnificent, gravity-fed aqueducts. Most did not survive the collapse of the Empire and by 1570 only one remained functioning, the Aqua Vergine. Over the next fifty years, a series of energetic, indeed remarkable popes transformed the city’s water supply as eighteen new fountains were set up all over the city. Some of these were spectacular sculptural monuments in their own right, such as the Acqua Felice built by Pope Sixtus V Peretti (the so-called ‘Engineer’ pope) and the Aqua Paola built for the Borghese pope, Paul V. In addition, hundreds of ornamental drinking fonts and drains serviced the domestic needs of everyday Romans whilst carefully sited piped water made it possible to transform great public spaces such as at Piazza Navona into aquatic ‘stage-sets’ on important Feast Days. Indeed, the cultural significance of water in Rome’s Baroque evolution is nowhere more iconic, and spectacular, than at the Trevi Fountain, begun in the 1450s and not completed in its present form until 1762, thus marking both the start and finish of the city’s transformation.