Sylt, a crocodile-coloured smudge in the Frisian archipelago, has been dissolving into the ocean since it emerged as an island eight centuries ago. Each year approximately 1m of coastline is lost; it costs Germany an annual €10mn to pump the seabed back onto the shore. You can see the sediment sweeping across the wild heathland, over thatched roofs and out into the North Sea. Legend has it that visiting children have been asked to shake sand out of their shoes before leaving. Even sandcastles are said to be forbidden.

The arrival of Lanserhof, then, is an ironic proposition: a medical resort bent on prolonging life, built on a shifting landmass that might not survive another 100 years. But Lanserhof is determined to spread its roots: perched among the sand dunes of List, the island’s most northerly town, the €120mn, 20,000sq m development peeps out at the horizon from under a colossal thatched roof (the largest in Europe). Inside, 55 rooms and suites mirror the heather-flecked surroundings with soft woods, slate greys and mossy suede. The wellness side, however, is serious business, offering more than an acre’s worth of stark white treatment rooms, gym space and an indoor-outdoor saltwater pool. 

It’s a luxury concept for a luxury island, part of the most expensive district in Germany and where a 100sq m property will set you back around €1.8mn. Prices have been rising steadily since the 20th century, when Sylt began playing host to notable German holidaymakers who came for the marine climate and brisk sea winds. Marlene Dietrich brought her violin, Gunter Sachs cruised the beaches on a BMW Motorrad and footballer Günter Netzer became a regular at F?hrhaus Sylt, a five-star hotel overlooking the tidelands.