Chenonceau is the only château in France built across a river. The first section — a square manor with round corner towers — was built between 1513 and 1522 by Thomas Bohier's widow Katherine Briçonnet. Henry II gave it to his mistress Diane de Poitiers, who built the first bridge across the Cher. His widow Catherine de Medici then took it back, added the two-storey gallery on top of Diane's bridge, and held royal court here through the worst years of the French Wars of Religion.
It's called the Ladies' Château — 'Le Château des Dames' — because the six women who shaped it matter more than any of the men who owned it between. After the Medicis came Louise of Lorraine (who painted her bedroom black when her husband Henry III was assassinated), Madame Dupin (who ran a salon here through the Enlightenment and saved the château from the Revolution), and Marguerite Pelouze (who restored it in the 1860s).
Today the Menier family — yes, the chocolate people — have owned and operated Chenonceau since 1913. Because it's private, the tickets don't go through the Centre des monuments nationaux. The château is open every day of the year except Christmas.