The water comes and goes twice a day on the coast of North Friesland in the far north of Germany. At low tide it exposes the Wadden Sea. This is 40 kilometers wide in places and is home to ten times more animals than other seabeds. Countless small animals - shrimp, sand crabs and cockles - in turn attract large flocks of birds. The Schleswig-Holstein Wadden Sea is part of the largest national park in Germany and has been part of the UNESCO World Heritage since 2009. The Halligen are unique in the world. There are ten of them, all located in the North Frisian Wadden Sea, often only accessible by lorry or ship. Unlike islands, Halligen are flooded several times a year and are still inhabited. The North Frisians built their settlements here on so-called mounds. These are hills that lie above the water surface even during storm surges. Life on the Halligen is more leisurely than on the mainland.