Aosta

• Saint-Martin-de-Corléans Megalithic Area with artifacts and tombs dating to the Neolithic era.

Tour du Lépreux.

The ancient town walls of Augusta Prætoria Salassorum are still preserved almost in their entirety, enclosing a rectangle 724 by 572 metres (2,375 by 1,877 ft).[8] They are 6.4 metres (21 ft) high, built of concrete faced with small blocks of stone. At the bottom, the walls are nearly 2.75 metres (9.0 ft) thick, and at the top 1.83 metres (6.0 ft).

Towers stand at angles to the enceinte and others are positioned at intervals, with two at each of the four gates, making twenty towers in total. They are roughly 6.5 metres (21 ft) square, and project 4.3 metres (14 ft) from the wall. Of the 20 original towers, the following are well preserved:[9]

• Tour du lépreux (French for Leper's Tower), was given this name after a leper called Pierre-Bernard Guasco was jailed there in the late 17th century. Le lépreux de la cité d'Aoste, a novel by Xavier de Maistre, is also named after this leper.
• Tourneuve (13th century).
• Tour du Pailleron.
• Tower (Castle) of Bramafan, built in the 11th century over a Roman bastion. It was the residence of the Savoy viscounts. In Franco-Provençal, Bramé la fan means "To scream for hunger".
• Tour du Baillage.
• Tour Fromage.

The east and south gates exist intact. The latter, a double gate with three arches flanked by two towers known as the Porta Praetoria (1st century AD) was the eastern gate to the city, and has preserved its original forms apart from the marble covering.[10] It is formed by two series of arches enclosing a small square.

The rectangular arrangement of the streets is modeled on a Roman plan dividing the town into 64 blocks (insulae). The main road, about 10 metres (33 ft) wide, divides the city into two equal halves, running from east to west. This arrangement makes it clear that guarding the road was the main raison d'être of the city.

The Roman theatre, of which the southern façade remains today, is 22 metres (72 ft) tall.[11][12] The structure, dating from the late reign of Augustus, occupied an area of 81 by 64 metres (266 by 210 ft); it could contain up to 4,000 spectators. In the nearby was the amphitheatre, built under Claudius. A marketplace surrounded by storehouses on three sides with a temple in the centre with two on the open (south) side, as well as a thermae, have also been discovered.

Arch of Augustus.

Outside the town walls is the Arch of Augustus, a triumphal arch in honour of Augustus, built in 35 BC to celebrate the victory of consul Varro Murena over the Salassi.[13] About 8 kilometres (5 miles) to the west is a single-arched Roman bridge, called the Pont d'Aël. It has a closed passage, lighted by windows for foot passengers in winter, and above it an open footpath.

Aosta Cathedral.

There are considerable remains of the ancient road from Eporedia (modern Ivrea) to Augusta Praetoria into the Aosta Valley. The modern railway follows this route, notable for the Pont Saint-Martin, which has a single arch with a span of 35 metres (115 ft) and a roadway 4.5 metres (15 ft) wide; the cutting of Donnas; and the Roman bridges of Châtillon (Pont Saint-Vincent) and Aosta (Pont de Pierre).

• The Cathedral, built in the 4th century and replaced in the 11th century by a new edifice dedicated to the Madonna. It is annexed to the Roman Forum.
• The Romanesque-Gothic Sant'Orso (Saint-Ours). Its most evocative feature is the cloister, which can be entered through a hall on the left of the façade. It is dedicated to Ursus of Aosta.
• The Saint-Bénin College, built about 1000 by the Benedictines. It is now an exhibition site.
• The Bridge of Grand Arvou, a medieval arch bridge-aqueduct, is located in the frazione.