Sea salt mounds, Camargue, France. Salin de Giraud, the largest sea salt works in Europe, stores the salt in great mounds, or camelles, up to 21 meters high. The salt pans are filled with sea water between March and September where sun and wind evaporate the water and the saturated solution is crystallized into salt. Salt has been harvested in the Camargue since Roman times but it became an industry in the 19th century. Around 1 million tonnes are produced each year and the salt is primarily used for de-icing roads and industrial products some of which are manufactured into sodium carbonate for the Marseille soap industry, across the Rhone. The production and trading of salt in this area has been carried out for two thousand years, with the product often transported by boat along the Mediterranean coast.