Rome is one of the world’s most hallowed pilgrimage destinations. Each year, the Eternal City’s numinous qualities draw millions of devout Christians to undertake a pilgrimage there just as they have for nearly two millennia. Visiting the most venerable sites, culminating with St. Peter’s, the Mother Church of Catholicism, the processional journey often reinvigorates faith among believers. It is a cleansing experience for them, a reflective pause in their daily lives and yearly routines. Millions more arrive in Rome with more secular agendas. With equal zeal they set out on touristic, educational, gastronomic, and retail pilgrimages. Indeed, when in Rome, I dedicate at least a full and fervent day to “La Sacra Giornata di Acquistare le Scarpe,” the holy day of shoe shopping, when I visit each of my favorite stores like so many shrines along a sacred way. Although shoes are crucial to our narrative and to the completion of any pilgrimage conducted on foot, our interest in this essay lies elsewhere, in rededicating Rome’s vital role as a city of reflective pilgrimage by divining water’s hidden course beneath our feet (in shoes, old or new) as it flows out to public fountains in an otherwise parched city. Just as streams of religious pilgrims flow through the Eternal City, sustaining and reinvigorating it with every step, so too the flow of water through Rome nourishes and rejuvenates the city with every drop...