The Wadden Sea is the largest unbroken system of intertidal sand and mudflats in the world, stretching from the Netherlands across northern Germany to Denmark, and Sylt sits on its outer edge. The eastern side of the island, facing the mainland, is part of the Schleswig-Holstein Wadden Sea National Park — the whole area is also a UNESCO World Heritage Site, awarded for the extraordinary biodiversity of the tidal ecosystem and the millions of migratory birds that depend on it.
The best way to see it is on a guided mudflat hike (Wattwanderung) at low tide. Tours start from Hörnum in the south, from List in the north, or from the Wadden Sea Centre in Keitum. Walking barefoot across the flats, with seals visible on the sandbanks and the smell of salt and silt in the air, is unlike anything else on the German coast.