Nantes' quirkiest sight is this fantasy world on the site of the old shipyard – a serious and seriously wacky workshop inspired by only-in-France creativity that brings together Jules Verne’s fecund imagination, Leonardo da Vinci’s mechanical wizardry and the city's history of excellence in engineering. Kids will absolutely love the wondrous metal, wood and steel creatures that spring to life thanks to electricity and hydraulics.
The Galerie des Machines (adult/child €11/9) is a mechanical bestiary whose 16 creatures "come alive" and even fly, one at a time, when the guide flips the switches. The 50-minute tours are in French but that hardly matters when there's so much to see (a printed sheet in English is available). On the other side of the covered passage, you can peer down into the Atelier (workshop), where the site's wondrous creatures are built and repaired.
The highlight here is the Grand Éléphant (adult/child €9.50/7.50), a 12m-tall, 48-tonne mechanical pachyderm that – and this is no exaggeration – has to be seen to be believed. Up to 12 times a day, it sets out on "walks" around the site with up to 50 passengers aboard – but it's almost as much fun to watch the beast as it sprays water at shrieking kids as it is to ride.
Across the cement expanses of the one-time dry dock, the Carrousel des Mondes Marins (adult/child €9/7), a three-story fun fair merry-go-round, is a "mechanical aquarium" filled with giant mechanical crabs, octopuses and other strange sea creatures. You can explore all three levels before choosing where to sit.
The massive concrete structure to the left as you approach Les Machines de l’Île is Blockhaus DY10, a WWII German bunker constructed to shelter German soldiers and French shipyard workers from Allied air attacks.
The basic entrance fee covers admission to both La Galerie des Machines and the actual workshop; separate tickets are required for the 40-minute elephant ride and Le Carrousel des Mondes Marines. Advance reservations for the elephant rides are highly recommended. Closed on Monday except during French school holidays; open only in the afternoon in winter; closed early January to early February.
