Castle of the Duke of Brienne🏯.
Although Nantes is a medium-sized city in France, it feels relatively quiet and not crowded, but the urban area is also the essence, especially the area near the castle. The castle is free, the moat has dried up, and only grass and mice are left. The ancient stone walls have witnessed the vicissitudes of history. After the tour, you can go to the side and order a steak and a beer🍺about 20 euros, which is much better than Paris.