In the context of the climate crisis and the accompanying social change, the project explores the relationship between Berlin and the Spree, the urban space and the citizens. How can the river be given its own “political” voice and what can help to create more awareness about the Spree and the influence us humans have on it? With the help of the buoy developed in the project, the actual state of the river is communicated to citizens* in an accessible way.In the hot summer months, the buoy also pumps oxygen into the river and supplies it to the Spree and its creatures