We don't really know whether it's fair to call the Cité de l'Océan a mere 'museum'. At heart it's simply a museum of the ocean but this is entertainment, cutting-edge technology, theme park and science museum all rolled into one. During a visit you will learn all you ever wanted to know about the ocean and (sort-of) ride in a submarine to watch giant squid and sperm whales do battle.
It's all very child friendly (although many displays are a bit complicated for younger children), but it's equally fascinating and fun for adults. A combined ticket with the Musée de la Mer costs €18 for adults and €13 for children. Family tickets are also available. In July and August a free navette (shuttle bus) runs between Musée de la Mer and the Cité de l'Océan.