The terminal of the legendary transatlantic liner is home to the Cité de la Mer maritime museum. The Grande Galerie des Engins et des Hommes presents a dozen bathyscaphs and submarines. A visit of the Redoutable, France's first nuclear submarine, provides a fascinating insight into this domain (including simulators and interactive exercises). The Océan du Futur has 17 aquariums, tackling themes of the exploration of the oceans, their biodiversity, food resources, pollution etc. A fun and instructive voyage.