Arco di Augusto / Arc d'Auguste

The Arch of Augustus in the center of Aosta is one of the best-preserved single-arch Roman triumphal monuments in existence, standing since 25 BC when it was erected to celebrate Emperor Augustus's victory over the Salassi, the Alpine tribe that had controlled the mountain passes toward Gaul. It was built in the very founding year of the Roman colony Augusta Praetoria — modern Aosta — making it a direct physical trace of Rome's northward expansion. The original marble cladding has largely weathered away, but the stone core remains fully intact. Designated an Italian national monument, the arch straddles what was once the Via delle Gallie, meaning visitors who pass through it today are walking the exact line of the ancient Roman road.