In the heart of the Roman city, in the Augustan age was built this reticulated theatre in two colours that exploits the natural slope of the mountain. The auditorium, designed for spectators, has semicircular tiers running vertically of five stairs and is divided into two sections, upper and lower. In the highest part there are traces of a vaulted gallery. Two corridors allowed direct access from outside to the orchestra pit and for the stage there were three gates. The theatre can accommodate about 2,000 people, and even today is used for performances especially in the summer when it hosts important cultural and theatrical events.