The forest is an interwoven system - resistant and fragile at the same time. It has survived the ice ages and forms the habitat for countless inhabitants. The audio walk :hearing the unknown invites you to a mindful walk. A voice in your ear guides you into the living worlds of groups of trees, families of fungi and microorganisms. They are in permanent exchange - sometimes connected over great distances. In :hearing the unknown, invisible biotopes become perceptible and inaudible signals can be experienced sensually.:hearing the unknownHow do the communications of trees and fungi sound? What does a twig feel when touched? How do plants perceive us? With the help of a biotechnological recording device, electrical signals between trees, fungi and plants are transformed into music. Combined with field recordings of the environment, a composition and story about the forest ecosystem is created. We will meet many creatures, change perspectives and perhaps re-locate ourselves in the end. A journey begins between microbial clouds and treetops, between the forest and outer space.