On the isolated hill of Montorfano between Lake Maggiore and Lake Mergozzo is a quarry of fine white granite which has been an important economic resource for the Verbano Cusio Ossola area.

This great quarry has for centuries provided the stone for major structures all over Italy. As an example, in 1830 stone was quarried to build the 82 columns of the Basilica of San Paolo Fuori le Mura, and transported to Rome on a lengthy journey entirely by water.

The same granite was used to build the little Romanesque Church of San Giovanni Battista (John the Baptist) in the hamlet of Montorfano, one of the most interesting and best preserved Romanesque churches in the area (11th-12th centuries). Recent excavations have revealed traces of previous buildings dating from the 5th-6th and 9th centuries. The cruciform church contains the remains of a Paleochristian baptismal font, while outside are the remains of an early medieval basilica with three apses.

Many archaeological finds from here and other sites in the area are kept in the Antiquarium Museum in Mergozzo.

You can walk to Montorfano along the so-called Sentiero Azzurro (“Blue Path”), a hiking route along the shore of Lake Mergozzo starting from the village of the same name. Once a bay of Lake Maggiore, Lake Mergozzo is popular with visitors and local people alike.