Wadden Sea National Park.
Introduction
Stretching from Denmark to the Netherlands, Wadden Sea is Germany's largest national park. It is divided in five administrative sections, including three in Germany: Lower Saxony, Hamburg and Schleswig-Holstein. They cover respectively 2,777 km², 137 km² and 4,410 km² of salt marshes, mudflats, beaches, dunes and estuaries. They are ideal for birdwatching, walking and swimming.
Please check the official website for more information.