Some 1,7 miles (2.75 km) from the Fort de la Hougue, the Fort de Tatihou secures the pass that leads to the port of Saint-Vaast-la-Hougue over 69 acres (28 ha). Completed in 1699, its Vauban tower also has an adjoining turret whose spiral staircase, with a semi-spherical dome, serves the three floors. The fort also houses barracks, stores, a vast powder magazine covered with earth, and a chapel from 1714 dedicated to Saint Clement, the patron saint of sailors.