You have to see the Piazza dei Signori, the heart and soul of the city.
Here you will find the Palazzo dei Trecento and a soaring bell tower (campanile).
Enter the building through a large external staircase to see sculptures and artworks.
You might also have to visit the piazzetta Monte di Piet to visit the Cappella dei Rettori to see its frescoes, ornately decorated wooden and leather panels, paintings by such as Luca Giordano and Sebastiano Ricci, as well as displays of artifacts used for weighing and measuring.
Then visit the late Romanesque-Early Gothic church of San Francesco, built by the Franciscan community in 1231-1270. It was reopened in 1928. The interior has a single nave with five chapels. On the left wall is a Romanesque-Byzantine fresco portraying St. Christopher (later 13th century).
The Grand Chapel has a painting of the Four Evangelists, by a pupil of Tommaso da Modena, to whom is instead directly attributed a fresco of Madonna with Child and Seven Saints (1350) in the first left chapel. The successive chapel has instead a fresco with Madonna and Four Saints from 1351 by one Master from Feltre.
The church, among the others, houses the tombs of Pietro Alighieri, son of Dante, and Francesca Petrarca, daughter of the poet Francesco.
The Loggia dei Cavalieri is a wonderful example of Treviso's Romanesque influenced by Byzantine forms.
It was built under the podest Andrea da Perugia in 1276 as a place for meetings, although reserved only to the higher classes.
Church of San Nicol, a mix of 13th century Venetian Romanesque and French Gothic elements.
The interior has a nave and two aisles, with five apsed chapels. There are also important frescoes by Tommaso da Modena, depicting St. Romuald, St. Agnes and the Redemptor and St. Jerome in His Study. In the eastern area of the church there is also the fresco of St. Christopher , which is the most ancient depiction of glass in Europe. The Duomo, dedicated to St. Pietro. Built in the Late Roman era, the duomo was once a small church , to which later were added a crypt and the Chapels of the Santissimo and the chiostro in 1520.
After the numerous later restorations, only the gate remains of the originary Roman edifice. The interior houses works by Il Pordenone and Titian among the others.
The edifice has seven domes, five over the nave and two closing the chapels.