Explore the hidden past of Nantes' buildings

Nantes has a lengthy history dating back nearly 2,000 years, which features a colourful cast of Celtic and Roman settlers, medieval invaders, sea-faring traders, modern industrialists and more. Given this rich and varied past, it's not surprising that this ancient port city has many stories to tell – and that many buildings and other locations have played several, often hugely different roles over the course of their lives.

Everywhere you look, multiple layers of history are hiding just beneath the surface of the modern-day restaurants, offices, hotels and shops you may pass by without a thought during your stay, without realising their former significance. Here are just a few of the sites with fascinating past lives that you can visit during your stay in Nantes…

The handsome neoclassical building now occupied by the Radisson Blu Hotel, Nantes served as the city's Palais de Justice for almost 150 years before the construction of the current modern courthouse in the late 1990s. Originally designed by local architects Saint-Félix Seheult and Joseph-Fleury Chenantais, the impressive structure was first used in 1852 and has played host to a number of important legal cases and drama over the years.

After the courts moved to their new home in 2000, the colonnaded structure was sensitively renovated by designer Jean-Philippe Nuel and architects from the agency DTACC to become Nantes' first four-star luxury hotel, while still preserving its most distinctive features.

Trempolino Arts Space – formerly a World War II bunker

Trempolino is just one aspect of the quirky La Fabrique arts lab – a multi-purpose space designed to support, promote and showcase local artists and performers. The Trempolino building's distinctive silhouette is the result of the structure being built on top of a German bunker – or blockhaus – dating from the Second World War, when Nantes was occupied by German troops for four years. Today, the unusual building contains a variety of recording studios and rehearsal rooms, as well as space for workshops, exhibitions, gigs and more in the basement café nestled within the walls.

A particular highlight of many people's holiday in Nantes is a trip to see Les Machines de l'Île, a unique cultural and tourist attraction consisting of giant "machines" – currently an elephant, a heron and a carousel, which can be ridden by visitors – inspired by the futuristic adventure stories of locally-born author Jules Verne and the mechanical inventions of Leonardo da Vinci.

These mechanical creatures are housed on the former site of the Chantiers de la Loire shipbuilding yards on the l'Île de Nantes, which was the location of the city's main harbour until the 1970s, when much of the focus moved downriver to Saint-Nazaire. The massive concrete and metal warehouses where the attraction is based were built in the early 20th century as metalworking shops for the shipyards, and were a key focus of the city's industry.

This branch of the popular French retail chain Fnac occupies a particularly grand venue – an imposing listed building that formerly housed the city's bourse du commerce, or commodity exchange, where a variety of goods were bought and sold by merchants and investors. The Palais de la Bourse was built between the late 18th and early 19th centuries in the popular neoclassical style, and was once adorned with statues and decorative clocks. Unfortunately, much of this was lost when the building was struck by bombs during the Second World War, although the building was extensively reconstructed afterwards and granted protected status as a historic monument. The interior was completely renovated when Fnac moved in, but you can still imagine the building's past as you browse through the shop.

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Le lieu unique is today Nantes' dedicated center for contemporary arts, hosting a varied programme of theater, music, dance, visual arts, literature and more throughout the year. The vast, airy building with its distinctive clock tower now encompasses a variety of performance, exhibition and social spaces that make it a favorite gathering place for the local community – but previously it was a biscuit factory owned by manufacturer Lefèvre Utile (better known as LU), a globally recognised brand founded in Nantes. The structure was partially demolished in 1974 and subsequently was unofficially adopted by the local arts scene, before being purchased by the city and renovated into the dynamic cultural centre it is today.

Nowadays the pretty Île de Versailles in the centre of the River Erdre is home to a peaceful Japanese-style Zen garden, as well as an exhibition space with aquariums and a restaurant. However, for centuries there was no island on this site at all – simply a stretch of marshy ground.

In 1831, the island was artificially created with the earth and other materials removed during the digging of the canal between Nantes and Brest, and subsequently served as a base for several industries, including tanneries, forges and shipbuilding before being largely abandoned in the 1950s. It was only after the city acquired the island in 1986 that the vision of the island as a public green space was put in place, and today it is a charming oasis which is widely admired for its exotic landscape of rock gardens, ponds and waterfalls interspersed with bamboo, rhododendrons and cherry trees.