In my opinion, one of the most beautiful structures in France is Chenonceau. Situated on the River Cher in the Loire Valley, it is extremely picturesque. Built and re-built since the 11th century, the existing chateau was built in 1515. Henry II gave it to his mistress, Diane de Poitiers in 1547 and she made it her own. After Henry II's death, his widow, Catherine de Medici had her evicted! The Renaissance interiors have been well-preserved, with many original furnishings. Well worth a visit!