Sankt Peter-Ording

Sankt Peter-Ording is on the Eiderstedt peninsula in Schleswig-Holstein, facing the North Sea across the Wadden Sea — the tidal flats that run from the Netherlands to Denmark and are a UNESCO World Heritage site. The beach is around twelve kilometres long and, at low tide, up to two kilometres wide.

It is defined by that width and by what was built on it. Because the sea withdraws so far, the beach's restaurants and lifeguard stations stand on wooden stilts several metres above the sand — the Pfahlbauten, the stilt houses, which are the town's emblem and a practical response to a shore that floods twice a day. Walking out to one of them is a fifteen-minute proposition at low water.

The Wadden Sea behind is the reason for the World Heritage listing: the largest unbroken system of intertidal sand and mud flats in the world, and a critical staging ground for millions of migratory birds. Guided mudflat walking — Wattwandern — is a regional institution and is done with a guide because the returning tide moves faster than people expect and channels fill from behind.

Development is a spa town of some four thousand people, with a sulphur spring, a promenade and a well-organised beach economy. Wind is constant, which has made this the centre of German kitesurfing and windsurfing, and sections of the sand are given over to it. Vehicles are permitted on marked areas of the beach, which surprises visitors. The peninsula's other side faces the Eider estuary and is quieter entirely; the whole of Eiderstedt is reclaimed marsh behind dykes, which is why the land behind the dune is flat, green and below the level of the sea at high tide.

Restaurants on stilts because the beach floods twice a day, two kilometres of sand between the dune and the water at low tide, and the largest intertidal system in the world behind it. Walk the mudflats with a guide — the returning tide fills the channels from behind, which is how people get caught. The North Sea is eighteen degrees in August.