Arcachon Bay

The basin is an almost enclosed lagoon of around one hundred and fifty square kilometres, joined to the ocean by a mouth a few kilometres wide between the Cap-Ferret point and the Pilat dune. Twice a day the tide drives considerable volumes in and back out through those channels, and the range reaches four to five metres on spring tides. At low water a large part of the surface is uncovered: banks of sand and mud known here as crassats, cut through by channels where the water keeps running. The same expanses are therefore beach in the morning and channel in the afternoon, and that is the first thing to understand before taking a boat out. South of the mouth, the Pilat dune rises above one hundred metres — its exact height changes from year to year, the wind reshaping it constantly — and it is the highest sand dune in Europe. Driven by the westerlies, it advances inland by a few metres a year and slowly buries the forest it borders. That forest is itself recent: the maritime pines covering the Landes de Gascogne were planted from the nineteenth century onwards, under the law of 1857, to fix the moving dunes and drain unhealthy marshland. At the head of the basin, the Leyre delta forms a different landscape of reed beds and salt meadows; the Teich bird reserve takes in migrating birds there in autumn and spring. Oyster farming has held the basin since the nineteenth century, and makes it one of Europe's leading centres for collecting spat: young oysters settle naturally on collectors here, then leave to grow on elsewhere along the French coast. The beds occupy the foreshore, marked out with stakes, and the growers' huts line the villages of the northern shore — L'Herbe, Le Canon, Piquey, Piraillan, La Vigne — built of painted timber, doors open onto the channel. Oysters are eaten standing, opened on the spot, with bread and white wine, facing the beds that produced them. In the middle of the lagoon, the Île aux Oiseaux emerges at low tide around its two cabanes tchanquées, raised on stilts and now the most reproduced image of the basin. Arcachon, on the southern shore, was built as four quarters named after the seasons. The Ville d'Hiver, laid out from 1860 by the Pereire brothers, occupies the wooded dune behind the seafront: hundreds of fretwork timber villas were built there for patients sent to breathe the pine air, and most still stand, in a maze of curving lanes sheltered from the wind. The seafront belongs to the Ville d'Été and its piers. On the northern shore, Cap-Ferret lines up low houses under the pines, plainer, often timber-built, and a lighthouse whose two hundred and fifty-eight steps give the only overall view of the basin. The pinasse, a flat-bottomed boat with a raised stem, is still the boat of these waters: it goes where the draught rules everything else out. A stay here is set by the tide table rather than the clock: the crossing to Cap-Ferret, the trip to the Île aux Oiseaux, swimming and access to some beaches all depend on it. The bicycle is often the quickest way round, the peninsula being crossed by cycle paths where the single Cap-Ferret road jams in summer. The rest comes down to very little: forest on one side, ocean on the other, and between them a sheet of water that rises and falls twice a day.