The Sant’Ignazio military fort stands on the Colle di Sant’Elia. It was built in 1793 when the House of Savoy ruled the island, to combat French military attacks. It was the chief engineer Franco who drew up the project, inspired by the French fortifications designed by the engineer Vauban. Its layout included 5 bastions, and symbolically resembled turtles and was the result of modern studies on ballistics.
The work made slow progress due to a lack of funds and therefore manpower. It was interrupted in 1795, leaving the work incomplete.
In January 1804, the fort was temporarily set up as a hospital, to assist the nearby leper hospital.
In 1848, with the abolition of the Society of Jesus, the structure housed the Jesuits expelled from the churches of San Michele and Santa Teresa in Cagliari.
Its final usage before falling into its current state of abandon was during the Second World War, when it became an aircraft lookout point.
Although the fortress of Sant’Ignazio is in a state of disrepair, it can still be visited by walking about 950 m to the lighthouse at Capo Sant’Elia.
