The Bassin is the estuary of the river Eyre, one of the principal rivers of Gascony. The Bassin is renowned for its oyster farms which were once praised by Rabelais and are now, together, the fourth-largest producers in France. The basin includes 10 sleepy villages that arc their way leisurely around the 35km stretch of ocean beaches, from Arcachon in the south to Cap Ferret in the north.
The basin itself is open to the mercy of the Atlantic but, with its lake- like shape, forms a protective ring from the ravages of the sea. In the centre of this ring is the le aux Oiseaux, the Bassin's only island and now a protected bird sanctuary. Its dainty dimensions are home to seabirds, oysters and the picturesque cabanes tschanquees, little wooden huts on stilts.
At the bottom of the basin, the fishing village of Arcachon was a quiet little place that pretty much kept to itself until the middle of the 19th century. Then the railway from Bordeaux was extended to the village and, ever since, Arcachon has enjoyed immense popularity with holiday- makers.
Most of this popularity is due to the vision of the enterprising Pereire brothers, who divided the residential sections of the resort into a four- seasons theme and created a fashionable, pretty resort, complete with winding streets. Of the four seasons, it was the Ville d'Hiver with its elaborate faux-Moorish casino - modelled on the Alhambra in Granada and the Great Mosque of Cordoba - that captured the imagination of regular visitors such as Debussy, Alexandre Dumas, Chopin, Napoleon III and Toulouse- Lautrec.
They in turn were followed by the Bordelais who needed a location for their extravagant holiday homes, and soon Arcachon had become a riot of pastel-coloured villas, an architectural mishmash of Neo-Gothic, Tyrolean and Tudor. The casino burned down 20 years ago, but about 200 of the original villas remain, along with the many less ostentatious but equally appealing oystermen's cottages that dot the edge of the basin.
For the best view of Arcachon, climb up to the Parc Mauresque. The gangway at the top, the Passerelle St-Paul, was designed by Eiffel and is reached by a 19th-century lift.
A short way south of Arcachon is the Dune du Pilat, Europe's largest sand dune and one which inspires a certain eerie awe of the sea. Eight thousand years of relentless buffeting from the ocean has resulted in a 105m-high and 2.7km-long mountain of shimmering, pale sand. The car park, a little walk away from the dunes, is surrounded by pine trees and does little to prepare you for the spectacle you are about to see.
When you've trudged the 190 steps to the top, you suddenly lay eyes on the breathtaking view of the entire basin and the endless horizon of the ocean stretching off into the distance. At sunset the light reflects off the sand and it is all you can do to stop yourself making a giant leap down the sandy slopes of the dune.
Further into the basin, towards the mouth of the river, is Le Teich, known for it crafts and its birds. As a marshy delta, it attracts hundreds of migratory birds, including the mute swan. What is now a Parc Ornithologique is divided into four sections, each with observation posts for viewing the various species.
A little way further down the delta, you can canoe for several miles to view the region's charming flora and fauna at close hand. Or, if that sounds too energetic, you can sit back and take the dinky tramway from Cap Ferret village to the beach and wade into the Bay of Biscay. And, when your trip has come to its end, you can climb to the top of the Cap Ferret lighthouse as the sun sets and bid a panoramic farewell to Arcachon and the Dune du Pilat.