The pavilions that form the plaza de armas are ground floor and floor and like the rest of the fortress are vaulted and bomb-proof.The island, forming the West front, includes accommodations for staff assistants, engineers, lieutenant-colonels, chaplains, and surgeons.Close the plaza de armas, North and South, two islands of pavilions, identical in its plant, which is intended for accommodation of officers. These buildings have arcades, and approximately in the Center are crossed by a tunnel that forms a hallway with nine vaults supported on four pillars.