From the south of Brittany to the Gironde Estuary via Les Sables d'Olonne, the Marais Poitevin, La Rochelle, the Ile d'Oléron and finally Royan, is made up of large beaches, rocky ledges and coasts, marshes and canals. The Atlantic Ocean is a force of nature with its waves and tides that shape and modify the landscape day after day.