Wangerooge sits at the eastern end of the East Frisian chain, seven kilometers off the German mainland and almost 8.5 kilometers long but barely two wide. It is the easternmost and smallest of the inhabited East Frisian islands. What makes it strange is that none of those measurements would have applied a few hundred years ago. The island used to migrate, pushed by North Sea currents that scraped sand off its western side and piled it onto the east. Whole villages were abandoned to the surf, then rebuilt further along, then abandoned again. Only when twentieth-century engineers wrapped the western dunes in groynes and breakwaters did Wangerooge finally hold still. The Westturm, the great Western Tower built in 1597, marks the memory of that movement: it was originally erected near the eastern end of the island and only ended up in the west because everything around it crept the other way.

The pier where the ferries from Harlesiel arrive is called the Kanonenbrücke - the Cannon Bridge - because in 1912 the Imperial German Navy built it to land heavy artillery on the island. It has long since been retired from military duty, but the name remains, awkwardly attached to a quiet marina full of yachts. The island carries its history this way, in repurposed military hardware. The most beloved landmark, Cafe Pudding, perches on a round dune hill along the beach promenade that was hollowed out into a bunker during World War II. After the war, occupying forces ordered it demilitarized; later, someone had the marvelous idea of turning the lump of fortified concrete into a coffee house. Now visitors sip cappuccinos on top of a former bunker named for a dessert.

On New Year's Eve 1944, two American B-17 Flying Fortresses returned from a bombing run on Hamburg in tight formation, threading the gauntlet of German fighters. One was hit. Falling, it collided with the bomber below it - and instead of breaking apart, the two aircraft locked together, ball turret to chassis, like, as observers later put it, breeding dragonflies. One pilot somehow took control of the entangled mass and steered the joined planes back across the German coast for an emergency landing. Most of the crew bailed out over Wangerooge. Two men stayed with the wreck and rode it down to a successful crash landing in a field. The island remembers the story still, the way islands remember things: improbable, specific, and true.

Cars are forbidden on Wangerooge. So are speed pedelecs, electric scooters, Segways, hoverboards, and e-skateboards. What is permitted: bicycles, handcarts, the volunteer fire brigade, two large electric taxis, a horse-drawn wedding carriage if you really insist. Visitors arriving at the small village railway station typically wheel their luggage to their lodgings on carts loaned out by their landlords. The total length of the narrow-gauge railway, the one Deutsche Bahn still runs as the only narrow-gauge line in its national network, comes to just 5.9 kilometers - barely long enough to require a timetable, except that the tides demand one. About 1,055 people live here year-round. In summer, the population swells past 7,000 a day. Most of them come, in the end, to do nothing in particular: to rent a Strandkorb, the hooded wicker beach chair that Germans treat as a kind of seaside throne, and to remember that haste was never part of the deal.