Basilica of Santa Maria Assunta

The patriarchal basilica of St. Euphemia, dating from the 6th century, is flanked by the baptistery and the 15th-century bell tower. Under the increasingly strict control of the Dukes of Venice, of which it was the mother church, and repeatedly involved in military confrontations due to its permanent rivalry with the neighbouring Patriarchs of Aquileia, the Basilica of Saint Euphemia began to decline from 1105 onwards, when the new Patriarch, Giovanni Gradenigo, chose to reside in the capital: Venice. However, the basilica retained ownership of the patriarchal pulpit even after the papal recognition of the Venetian residence of the patriarchs in 1177. In 1451, however, with the establishment of the new Patriarchate of Venice, the basilica was incorporated into the new diocese, losing the title of cathedral.

The Sanctuary of the Holy Virgin Marcelliana was built between 1841 and 1844 on an old medieval church. In 1939, the Franciscan monastery was built next to the church. After the Second World War, due to the increase in the population of the village of Panzano, the parish of the Madonna Marcelliana was created.

Monfalcone Cathedral was built between 1926 and 1929 on top of an old 18th-century church, traces of which can be seen behind the present cathedral. This church was itself the restoration or reconstruction of an ancient church of medieval origin. During the hostilities of the First World War, the bell tower collapsed on the building, eventually destroying the church. At the end of the war, the only remaining place of worship had to be rebuilt, hence the construction of the present neo-Romanesque building in the 1920s.