The Roman road of the Gauls, built to connect Rome with the Rhone Valley, has in the Donnas section one of its most characteristic and spectacular points, carved out of the living rock over a length of 221 metres.
In a place where in ancient times the rocky promontory plunged into the waters of the Dora, the Romans launched a real challenge to nature by carving out a living rock on which they could draw perfectly vertical walls and in whose bosom they cut the roadbed.
Exciting and unusual, here the Via delle Gallie gives its best by offering the spectacle of a vaulted passage 4 metres thick, 4 metres high and almost 3 metres wide that eloquently illustrates the amount of rock removed and shows all the refinement of a road engineering never again achieved until viaducts and modern tunnels.
In the Middle Ages it served as a gate to the village, which was closed at night; The other defences were of course: on one side the mountain and on the other the river.
A fundamental road, much used over the centuries, as evidenced by the deep ruts left by the passage of carts and the wear of the walking surface that has been patched and repaired at various points over time.
A little further on, on the right, we recognise the excellent profile of a milestone, also spared in the rocky bank, which informs us of the distance to Augusta Praetoria (the current city of Aosta): XXXVI miles (about 54 km).