This tour allows to visit some particularly precious places: among them the stairway built in the thick walls by the will of Gualtieri di Brienne; the Studiolo of Francesco I de’ Medici, a very elegant treasure  “of rare and precious things” and the Scrittoio of his father Cosimo I (more known as Tesoretto); in conclusion the huge trussed structure that supports the panelled ceiling of the Salone del Cinquecento.