The Wadden Sea (Waddenzee in Dutch, Waadsee in Frisian, Wattensee in Low German, Wattenmeer in German, Vadehavet in Danish) is the name for a body of water and its associated coastal wetlands lying between a section of the coast of northwestern continental Europe and the North Sea.
The Wadden Sea stretches from Den Helder in the Netherlands in the southwest, past the river estuaries of Germany to its northern boundary at Skallingen north of Esbjerg in Denmark along a total length of some 500 km and a total area of about 10,000 km2.
It is typified by extensive tidal mud flats, deeper tidal trenches and the islands that are contained within this, a region continually contested by land and sea. The landscape had been formed for a great part by storm tides.
The Wadden Sea is famous for the rich fauna, avifauna and flora. Today, a great part of the Wadden Sea is protected in cooperation of all three countries.