The Hindenburgdamm is the 11-kilometre rail causeway that has linked Sylt to the German mainland since 1927. Trains run constantly across the dam carrying passengers and the famous car-shuttle service from Niebüll, since road traffic has never been permitted on the embankment. From the carriages the view in both directions is of the open tidal flats of the Wadden Sea — at low tide a vast wet expanse, at high tide an inland sea.
The crossing takes about ten minutes by train but is more impressive than the time suggests. If you have the chance, take a window seat on the south side facing the islands of Föhr and Amrum. Mudflat tours often start near the dam's mainland end.