When it was designed and built, there was almost nothing around it, except for the hope of a more peaceful future. In the years that followed, small white houses began to appear around it, along a network of narrow lanes. Families of settlers from the Tunisian island of Tabarka lived in them, exhausted from years of harassment. Calasetta officially emerged in 1770, occupying the northwestern extremity of Sant'Antioco, but for thirteen years the control and defence of the territory and of the stretch of sea between the main island of the archipelago of Sulcis and that of San Pietro were guaranteed by the mighty tower that still stands in the historic village centre today.
Built from blocks of volcanic stone on a rocky base, the tower has a truncated cone shape and, from the top, at a height of eleven metres, it is possible to see for 20 kilometres.