Flaminio is where Rome decided to be modern. The quarter runs north from Piazza del Popolo along the old Via Flaminia, and over the last twenty years it has filled with the buildings the rest of the city wouldn't dare: Zaha Hadid's MAXXI, Renzo Piano's concert halls, a footbridge with no cars. This is the contemporary walk, and it's the one most visitors never take.
Start at Piazzale Flaminio, where tram line 2 — the oldest in the city — heads north. Make for MAXXI first: Hadid's poured concrete bends like ribbon, and the ground floor and courtyard are worth it even without a ticket. A few minutes on, Piano's Auditorium Parco della Musica sits as three lead-grey shells around an open amphitheatre; walk between them.
Then down to the river and the Ponte della Musica, a white arch built for walkers alone — stand mid-span for the Tiber both ways. Nervi's disused Stadio Flaminio is a short detour for anyone who loves concrete. Finish by walking Via Flaminia back through the Porta del Popolo to the great oval piazza, and Flaminio metro right beside it.