Chiesa di Santa Maria Assunta

There are no reliable sources on the year of foundation, and the 11th century has been suggested. The first official mention comes from a document of 1128 concerning a territorial dispute between Nanno and Portolo, which belonged to the ecclesiastical jurisdiction of Tassullo; in 1188 Santa Maria di Cles is explicitly mentioned in a notarial deed of sale.

Between 1507 and 1523 the church was restored and repaired after the poor condition in which it had long been. It became an archpriestly seat in 1619 and received its organ in 1643. In the 18th century the floors of the hall and the presbytery were redone and a sundial was installed on the south façade; in the 19th century the bell tower was completed and the whole building was enlarged, by demolishing the old façade and building a new one, opening two side chapels, fitting stained-glass windows and installing a stone pulpit.

The cycle of works in the second half of the 20th century brought the greatest surprise: during the work, in recent years, the remains of a building predating the church itself came to light, probably datable to at least the 4th century BC.