A cruise along the Erdre: When you join your riverboat, make time for an evening cruise excursion along the Erdre river, a pretty tributary of the Loire, which is lined with parkland, grand buildings and colorful houseboats, and was described by King Francis 1 as "the most beautiful river in France."
Les Machines de l'Ile: This is great fun, and a testament to the ingenuity and creativity that transformed the Ile de Nantes area from a derelict former dockyard to a vibrant artistic and cultural quarter. The vast hangars still stand, but their workshops are now devoted to creating fantastic mechanical machines -- like a gigantic elephant, an oversized heron tree and (new from 2016) a super-sized spider -- which not only delight locals and tourists, but are also exported around the world. Don't miss a ride on the surreal Merry Go Round of the Marine Worlds, which is populated by mechanized marine creatures straight out of a Jules Verne novel -- or a Tim Burton film. (Bd L?on Bureau; 33-8-10-12-1225; opening times vary widely. Broadly, the attraction is open 10 a.m. to 5 p.m. in summer and 2 to 5 p.m. in winter)
Chateau des ducs de Bretagne (Castle of the Dukes of Brittany): This former Ducal Palace, one of the most outstanding chateaux in the Loire region, reopened after extensive renovation in 2007 and now houses the Natural History Museum, which features some excellent interactive exhibitions charting Nantes' medieval beginning, its later involvement in the slave trade and, more recently, its experiences in the First and Second World Wars. Climb up to its ramparts for fabulous views over the city. (4 Place Marc Elder; 33-272-640-479; courtyard open daily, 8.30 a.m. to 7 p.m.; interior open 10.30 a.m. to 7 p.m., closed on Mondays)
Jardin des Plantes: This lovely botanical garden -- featuring species from Africa, Asia and America as well as Europe, alongside a stunning collection of camellias -- is a haven of tranquility set close to the city center, and right opposite Nantes' main railway station. (Rue Stanislas-Baudry; free entrance, open daily.)
Passage Pommeraye: This gorgeously ornate shopping arcade was built in the mid-1800s and features Grecian statues bearing wrought-iron lamps and a beautiful wooden staircase. It's the place to shop in Nantes and, with designer shops, offbeat jewelry and ceramics outlets and heavenly chocolatiers; it has something to suit every budget. (Rue de la Fosse; 33-2-40-48-7817; 8 a.m. to 8 p.m.)
Trentemoult and Ile de Nantes: A ferry ride will take you to this delightful former fishing village turned artists' quarter on the Loire's left bank. Alternatively, you can walk to it by crossing the Anne de Bretagne Bridge and heading right along the waterfront, past former warehouses that have now been transformed into restaurants and art galleries, a skate park and a market garden.
Here you'll also see Les Anneaux, an art installation of 18 brightly painted hoops spaced out along the Quai des Antilles that act as a kind of telescope through which to view the Nantes skyline and -- looking the other way -- the Loire snaking into the distance. At sunset they light up, and so are even prettier.
It will take you about an hour to walk from the boat dock through Ile de Nantes to Trentmoult and it's well worth doing, as Ile de Nantes lies at the heart of the city's creative vibe and Trentemoult is a charming jumble of colorful houses with some good restaurants on its waterfront.
Estuaire Nantes/Saint-Nazaire: Keep your eyes peeled for this open-air collection of artworks, which are scattered around Nantes and line the Loire's banks as far as Saint-Nazaire. They include a striking white-painted Lunar Tree, an offbeat zebra crossing and a gigantic tape measure.
Memorial to the Abolition of Slavery: This lies less than a five-minute walk from the boat dock and is well worth seeing; above ground, you'll find glass bricks set into the pavement, each bearing the name of a slave ship that operated from Nantes, a permanent reminder of the murkiest aspect of the city's past. Below ground, a passageway is lined with etched glass bearing comments and contemplations on the evils of slavery. (Quai de la Fosse; open daily; access is free.)