The Baltic Sea is in many ways a unique research subject – at the same time, it is a young sea, but also one of the busiest and most polluted seas in the world. It has been called a laboratory, a time machine, and a pilot, as the conservation methods that have been developed for the Baltic Sea are applicable around the world. At the University of Turku, biologists, geographers, historians and researchers in natural sciences and maritime spatial planning are focusing on the current challenges. Six researchers reveal how their research aims to improve the state of the Baltic Sea.