How is a rainbow actually formed? At the dome of the planetarium, we show how this beautiful phenomenon comes about. Then it's off to the underwater world to meet the rainbow fish! He bravely makes peace with a giant blue whale and finds new friends in the deep sea. Based on the books "Der Regenbogenfisch stiftet Frieden" and "Der Regenbogenfisch entdeckt die Tiefsee" by Markus Pfister, published by Nord-Süd-Verlag.