The classical theater, in which the premiere of Bakchen of Euripides took place, was replaced in the 3rd century BC by the Hellenistic theater. A semi-circular mound of earth was laid on which brick-built seats were placed. A digging around the round orchestra ensures the drainage of the rainwater. Underground rooms and hallways allowed the appearance and disappearance of actors and objects. The stage was slightly higher than the orchestra. There were devices which allowed to show special effects. The theater is used today, after a further modernization, for the annual Olympus Festival.