The origins of Guérande go right back in history. It has been harvested on the peninsula since the Iron Age. Even today, there are still 5 salt works from the Carolingian era still in operation on the marshes. In around 1500, these already occupied 80% of their current surface area. Up to 1660, with the development of maritime trade, 2,500 “œillets” (crystallisation ponds) were built. The last salt works were created on the Guérande basin in around 1800, and today over 10,000 “œillets” are in operation.