Individual visitors (in small groups formed on site) exceptional access to the underground passageways and towers of the medieval fortress built under the Renaissance Royal House. Thus, at the foot of the ramparts, they will enter the Garçonnet Tower, built in the 15th century on the orders of Louis X1, then to visit the Salle de Lys room, once the refectory for the guards. From there, they will make their way along the rampart walk which will take them to the ditches of the old watch tower, past the rooms containing lapidary fragments. The visitors then enter the maze of underground passages taking them to heart of the Minimes Tower.