Forget fusty furnishings – 32 stripped, light-filled rooms inside the restored Castle of the Dukes of Brittany house multimedia-rich exhibits detailing the city's history. Computer terminals allow you to tour the old medieval city, juxtaposed with images of today. Other exhibits to look out for include sobering documentation of the slave trade, and vintage scale models of Nantes' evolving cityscape. Admission includes temporary exhibitions too; audioguides cost €2. The grassy moat gardens and rampart walk are free to meander and picnic in at leisure.