In 25 BC, Augustus founded Augusta Praetoria Salassorum in the valley where the Great and Little St. Bernard passes converge. It was a strategic military colony controlling the Alpine routes to Gaul and Germania. The Romans built it as a miniature Rome: a triumphal arch, a theater, an amphitheater, a forum with cryptoporticus, two gates, and a complete circuit of city walls. 2,050 years later, almost everything is still standing. Aosta may be the most complete Roman city plan visible in any Italian city — you can trace the original decumanus and cardo (main streets), see the walls on three sides, and walk through a triumphal arch that Augustus himself likely passed under. All surrounded by Mont Blanc, the Matterhorn, and Monte Rosa. Valle d'Aosta guide →
Plan my Aosta visit →Arco di Augusto (25 BC): A single-arched triumphal arch standing at the eastern entrance to the city. Well-preserved, with a Corinthian order and a medieval crucifix added to the top in the 18th century (which somehow works aesthetically). Free, always visible. Porta Praetoria: The main city gate — a double-arched gate with three openings (central for vehicles, lateral for pedestrians) and guard towers. You walk through it into the city center. Roman theater: The southern facade stands 22 meters high — the tallest surviving Roman structure in Aosta. The cavea (seating) held 3,000-4,000 spectators. €10 combo ticket covers the theater + cryptoporticus + amphitheater.
Cryptoporticus of the Forum: An underground vaulted corridor running beneath the forum — used for storage, administration, or simply to level the ground. You descend into a perfectly preserved Roman tunnel. The city walls: Almost the complete rectangular circuit survives, with towers at intervals. Walk along the exterior (free) for the most complete picture of what a Roman colony looked like. Amphitheater: Inside the convent of Santa Caterina — partially visible, with the arena floor and some seating exposed.
Getting there: trains from Turin (2h, scenic Dora Baltea valley), Milan (2.5h). By car: 1.5h from Turin via A5. Tickets: Arch and walls free. Combo ticket (theater + cryptoporticus + amphitheater) €10. Duration: 2-3 hours for all Roman sites. The town is small — everything walkable in 15 minutes. Combine with: Courmayeur and Mont Blanc Skyway (40min), Gran Paradiso National Park (40min to Cogne), Castello di Fénis (15min, the most photogenic medieval castle in the Alps), fontina cheese tasting everywhere in the valley.