As the other reviewers say, Chambord, Chenoncau and Amboise including Leonardo's house are amazing. In addition, Saumur is especially beautiful from the outside as a classic medieval castle painted in a famous book of hours from the Middle Ages. Loches is quite frightening, having been used as a prison after being a fortress. Its medieval town is atmospheric, too. Chinon is made up of the ruins of three castles of Eleqnor of Acquittaine fame that hang gorgeously over the quaint town. There are also fascinating ancient hermit caves at the top of Chinon's hill. Azay le Rideau has a magical atmosphere from the outside, encircled by water. Langeais is beautifully furnished and has a second, older ruined castle worth visiting behind the furnished one.