Its ramparts, built and rebuilt from the 12th to the 18th centuries, make a bracing walk, with the stretch between the Saint-Philippe bastion and the Tour Bidouane opening up a vista along the whole Emerald Coast.
There is a long walk between the bastion and the coast.
It is believed that Leonardo da Vinci, whom Francois brought to the Loire Valley in 1516, participated in the design, especially of the central four-towered donjon ' which makes a dream palace out of a classically feudal castle keep ' and the celebrated double-ramped spiral staircase in the donjon's center, which enables people to go up and down without meeting.