Chenonceau is the third most visited castle in France (after Versailles and Fontainbleu). The original defensive castle was destroyed, except for one tower (La Tour des Marques), and the palace we see today was built. King François I confiscated from the prior owner, the finance minister of France, for embezzlement. His successor, King Henri II, gave it to his mistress Diane de Poitiers. Henri II died before his son reached his majority and his wife, Catherine de Medici, was regent for a number of years. She forced Diane de Poitiers to swap Chenonceau for another (much less desirable) castle, Chaumont.
In more recent history, the Cher River across which the castle is built, formed the dividing line between free and occupied France in World War II. People crossed the line into free France through the chateau. The lower hall was used as an infirmary during this time.