It is the only one of the ancient monuments whose remains are still visible in Martigny. A symbolique monument of the ancient town, it was built at the begining of the 2nd century. The work probably took place during the reign of the Emperor Trajan. Constructed simply, it could accommodate some 5,000 spectators, fans of violent games. It is still used today for various events. Every Friday from the beginning of June to the end of September a guided tour is offered, reservation required at Martigny Tourism.