With a main axis of 148 metres, the amphitheatre here is one of the most impressive of all the amphitheatres left behind by the Roman Empire. It offered 17,000 seats to accommodate a large number of pilgrims. Built against the hillside, it spread out as a semi-oval structure : unlike the more commonly encountered version, the upper terraces were only built on one side of the structure.

It is indicative of the number of pilgrims who came here to pray to Apollo Grannus (a Healer-God) and, more especially, to take advantage of the therapeutic virtues of the water on the “Highland” plateau.

Constructed around 80A.C., the amphitheatre is the shape of a half-oval, a shape adapted to the terrain but also characteristic of Gaul.

Abandoned at the end of the 4th century, the amphitheatre has kept part of its outer walls and some arches from the large axial corridor.

At the far end of the arena are two chapels (sacella) for worshipping the game’s divinities. A consecration for the God Mars and a small alter for worshipping Jupiter as well as Diane and Nemesis were found by Jollois under the south “sacellum”.