The San Giovanni Tower is located in the Marina of Tertenia and had the function of containing and repelling possible attacks by Saracens. The tower stands on a promontory, the view of which encompasses the stretch of coastline from Capo Sferracavallo in the north to the promontory of Torre Murtas in the south. Tied to the Tower of San Giovanni is the story of the alcaide Sebastiano Melis, who with his men resisted and repelled Saracen attacks around 1812, and the legend of Maria Pitzettu. According to legend, Mary was taken prisoner by Saracens to breastfeed a child of the sultan. A few years later she was freed and brought back to Tertenia. Some time later, the new king, who had become an adult, invited Pitzettu to Algiers for the celebration of his wedding. At the end of the festivities he begged her to stay but the woman attracted to her native country, recused herself from the kind offer, and leaving the court, returned to her homeland, enjoying the abundant donations and dying late in life