Located right on the shoreline, in the centre of Sesimbra Bay, Santiago Fort was constructed in the 17th Century, on the orders of King João IV. It was an integral part of the line of defences protecting the entrances to the Douro, Tejo and Sado rivers and was one of the most important strongholds along the Arrábida coast.
The military layout inside the fort has been well preserved, particularly the governor’s residence, the garrison outbuildings, the powder store and cisterns, the chapel and the dungeons.
The fort, which has been used as a cultural venue in recent times, is currently being renovated, so that it can house the future museum of the sea and other cultural centres.