Drawing of an iceberg, part of which is shown underwater. The iceberg is divided into three parts labelled using terminology from Sigmund Freud: ego, super-ego and id. The id part is totally submerged, the super-ego is mostly in the water with a small part of it exposed in the air, and the ego is mostly in the air with a small part underwater. It illustrates Freud’s theory about the unconscious mind, with the large submerged areas showing how much there is that people don’t know about themselves.