Waddenzee, Posthuiswad Vlieland.
The Wadden Sea is an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern continental Europe and the range of Frisian Islands, forming a shallow body of water with tidal flats and wetlands. It is rich in biological diversity.
At the end of June 2009, the Wadden Sea was declared an UNESCO World Heritage Site.