This is a formidable fortress protected by deep and wide moats and defended by six towers where Britanny pyramidical machicolations appeared. Inside is the government palace where many official feasts were held. The graceful Tour de la Couronne d'or and the well, whose wrought iron decoration shows the ducal crown, are particularly interesting. The Grand Logis is decorated with Gothic skylights and was built by François II to house the dukes of Britanny.