If your idea of a fantastic vacation means being by the water, visit Koos. No matter what you choose to do here, you're unlikely to get bored of those lovely views.
This water-surrounded land mass is in Mecklenburg-West Pomerania, but Koos of course isn't the only thing to see around these parts. If you've got time for more attractions, University of Greifswald is worth a look as well.