This mighty polygonal building protects the most vulnerable part of the ramparts; today it houses different sections of the museum: Egyptian and Greek collections (fine series of vases), paintings of the Côte d'Opale (Boudin, Corot), sculptures (Carpeaux, Pompon) and ethnography exhibitions including a remarkable collection of Alaskan masks (Yup'ik, Aleut, Haida and Sugpiaq).