The Roman tunnel, which had holes in the roof to admit light, linked the centre of the sacred area to a late Roman circular house of treatment building, also known as the Telesphoreion.Under the floor ran water which provided relaxing sounds. The purpose of the tunnel is to make a treatment with the sound of water and provide a cool place for the patients in the hot summer months. Before patients enter to this tunnel, they drank a sedative and slept here in the dormitories while non poisonous snakes crawl among them all night. They were told that the serpent god, Asclepius will talk to them in their dreams and give them a diagnosis. It was believed that the snakes carried the healing power of Asclepius. I