Campo de' Fiori is two different places depending on the hour, and the morning version is the one worth your time: a working market, not the evening's drinking square. Two and a half kilometres that pair the market with the craft lanes and grand palaces a few steps west — the loud and the stately, side by side.
Start in the campo among the fruit and flower stalls, under the hooded bronze of Giordano Bruno, burned here in 1600 and still facing down the Vatican. Slip south into Via dei Cappellari, the hatmakers' lane, where gilders and restorers still work behind open doors. Then the switch to grandeur: Palazzo Farnese, Michelangelo's hand in the cornice, and the dead-straight Via Giulia that Julius II drove through the medieval tangle, ivy-draped Farnese arch and all.
Pause at the skull-studded facade of Santa Maria dell'Orazione e Morte — the brotherhood of the dead kept a sombre house — then loop back along Via dei Giubbonari, the old tailors' street, brighter and busier, to the tram on Via Arenula.