The conservatory is on a lower level from the ground, on the West of the tarred road that is today’s square in front of the museum. It is Roman semicircular with stone seats having a capacity of three thousand spectators. It had had three passages that led to the exit in the South side and the stage to the North. It was initially constructed in the first century AC by Herod the Attic with marble seats and was destroyed by fire. When rebuilt, it was used for duels and races with wild beasts. It became useless with the domination of Christianity.

    Close to the museum was visible the monument of Midea and Jason’s children, Mermeros and Feritas, who were stoned to death by Corinthians, after Midea’s criminal act who – according to a second evidence - burned and strangled Glauki.