When you think of the French region of Brittany, many images may spring to mind: windswept beaches, medieval towns, plates of soft pink langoustines. A giant walking mechanical elephant, however, is probably not one of them. But this is exactly what visitors encounter at the Île de Nantes, a 337-hectare island in the centre of the city of Nantes, on Brittany’s western edge.

While Nantes is a pleasant city, with white and grey stone buildings flanking the mouth of the Loire River, it doesn't have the spectacular architecture, major historical significance or three-star restaurants of some of its French counterparts. So the city decided to create its own unique attraction: Les Machines de L'Île.

In 2007, Nantes opened the combined art installation and amusement park on the site of a former shipyard. Les Machines offers both carnival-style rides for which anyone can purchase a ticket, and smaller machines demonstrated by visitors selected from the crowd. The result is a kind of steampunk amusement park, and a breathtaking juxtaposition of old, new – and weird.

Les Machines is inspired by Jules Verne, who was born and raised in Nantes, and the installations feel like 19th-century science fiction come to life. Verne’s 1870 novel Twenty Thousand Leagues Under the Sea, for example, inspired the three-storey, 25m-tall Carrousel des Mondes Marin (Marine Worlds Carousel). Visitors can choose to ride on three levels of mechanical sea creatures: squid and crab on the lowest level, suspended fish on the second and boats and jellyfish at the top.

Since the carousel elements are moveable, adults and kids alike scramble into seats and buckle themselves into the mouths of giant fish or aboard boats, pushing pedals and pulling levers to make the machines rock and spew steam.

The island’s biggest showstopper, however, is a 48-tonne mechanical elephant. The creature, which carries 50 riders, stomps the entire length of the park – from the entrance, across the shipyard and past an old warehouse to the carousel, before looping back to discharge passengers and wait for new ones. The wild ride takes a half hour.

Inspired by Verne’s 1880 novel The Steam House, in which British colonists travel through India in a house wheeled by a steam-powered elephant, the ride gives passengers the chance to view Nantes’ warehouses, ships and 18th-century mansions from a unique vantage point 12m in the air – the equivalent of being on the third storey of a moving house. It also sprays water at unsuspecting observers.

Smaller machines are housed inside the soaring Galerie Des Machines (machine gallery), including a flying heron and a menagerie of prehistoric-looking metal bugs, spiders and other imaginary pedal-powered slithering insects, all fitted with seats for riders.

The absurdist feel of the Machines de L’Île doesn’t stop at the entrance gates, but seems to spill out into Nantes itself. Just down the street from the Machines, a comically oversized yellow tape measure that replaces millimetres with centimetres lies flung across a courtyard, as though it had fallen out of the pocket of the world’s largest architect.

And across the river from the Île, le Château des ducs de Bretagne, the hulking 12th-century castle in the city centre, features a labyrinth-like sculpture made out of sticks sitting in the middle of its moat. Like much of the art in Nantes, it is offered up without explanation, as though it spontaneously appeared overnight.