The Cathedral of Immaculate St. Mary dates back to the sixteenth century and is located in the historic center of the city. The long duration of its construction is found in the variety of styles, although the Catalan Gothic prevail. The Cathedral was certainly open to the cult in 1593, though not finished. Reconsecrated after several restorations, was completed with the neoclassical facade only in 1862. The exterior is characterized mainly by the high bell tower, one of the symbols of Alghero: the first phase of construction, is in late Gothic style, with the barrel octagonal, several pointed arched openings on the sides and a pyramidal spire covered with polychrome majolica. At the base of the tower is a doorway in flowery style. The prospectus, spread with a monumental portico with triangular pediment and central staircase. The interior has a Latin cross divided into three naves separated by pillars and columns of classic taste. In the aisles there are six chapels: significant especially the first, larger than the others and covered by domes, with impressive neoclassical altars. The presbytery is surrounded by a marble balustrade, by Giuseppe Massetti, who also designed the sculpture of the main altar and the pulpit. In the apse, there are five chapels in Gothic style that host valuable altars.