Tiresias was a man who was transformed onto a woman for seven years by the goddess Hera because he struck down two snakes who were mating. Afterwards he was released and allowed to become a man again. When Zeus and Hera were having an argument about who better experiences pleasure during intercourse, Tiresias - having lived as both a man and a woman - answered 'of ten parts, a man enjoys one only' thus taking Zeus's side. Hera blinded him in her anger at losing the argument but Zeus gave him the gift of clairvoyance and prolonged life.
Hence, Tiresias is a witness to the goings on of humanity. He is caught in this role of non-intervention and observance, even though he is blind.
And isn't that a great picture of an Unreal City? Thank you for your continued presence here.