Amiens

Amiens needs 1 day: Notre-Dame Cathedral, France's largest by interior volume and a UNESCO World Heritage Site, in the morning, and a boat tour of the Hortillonnages, floating market gardens on a network of canals cultivated since the Middle Ages, in the afternoon. April-September is best for the boat tour. It's inexpensive by French standards. The cathedral was the reference point for height and proportions for several later French Gothic cathedrals, and the Hortillonnages are still worked today by a handful of market gardeners who sell their produce at the city's floating market.