Santa Maria Novella is the architect's church — where Alberti turned a builder's problem into the most copied facade in Italy — and the walk pairs that geometry with the friars' pharmacy and a slow drop to the river. Two and a half kilometres, best in the afternoon, ending on a bridge in low gold light.
Start in the broad piazza, the Dominicans' preaching ground, and read the facade from the far end where it resolves into one design. Alberti's scrolls, joining wide church to narrow nave, are the move every later front borrowed; inside, Masaccio's Trinity invented vanishing-point perspective on a wall. Round to Via della Scala for the Officina Profumo, the friars' pharmacy mixing rose water since the 1200s — walk the frescoed halls whether or not you buy.
Then south down Via dei Fossi, antique-dealers and gilders all the way to the Arno at Piazza Goldoni. Turn along the Lungarno for the view the streets withhold, and end on Ponte Santa Trinita, rebuilt from its own dredged stones after the war, with the Ponte Vecchio framed gold upstream.
