See www.france-voyage.com. On the Sèvre Niortaise just east of the marshlands, Niort is a useful launch pad for La Venise Verte. Its old town centre is sandwiched between the huge car park of place de la Brèche and the river in a maze of meandering medieval streets which lead down to place des Halles. The covered market is here, and the small-scale Musée du Donjon, laid out in a 12thC keep.

It is worth seeking out Le Pilori, the former Town Hall, off rue Victor-Hugo. This delightful little four-square Renaissance building, with its corner towers, spitting gargoyles, decorative pediments and balustraded roof line, has been spruced up to serve as a temporary exhibition centre.

The tourist office has information about boat trips and walks in the Marais. Bicycles can be rented from the SNCF station. Niort is also the best place to stock up on picnic ingredients before heading into the marshes.