The centre of Treviso is the walled town; as seems to be common in Italian cities, it is largely pedestrianised. Probably a good thing - it's a bit of a nightmare to cross the city by car, and having all those cars ploughing through the centre wouldn't have done much for the town.
The citizens of Treviso seem to be largely ignorant of the fact that they are living in an archaeological goldmine. You only have to lift your eyes above the level of the ground floor to see old, gradually fading murals and designs (see below).
The cathedral (duomo) is more accessible than many seem to be - it is open to the public when there isn't a mass on. Again, its walls tell of vast amounts of history . The crypt (pay 0.30 Euros to switch the lights on - even I'm prepared to contribute that much to the funds of the Catholic church) dates back around 1000 years; I think the paintings go back around 700 - well back into the medieval era.
There is a lovely, placid river that flows along the southeastern edge of the city (see below). We had parked south of town and walked from the east to the south along the bank, watching small waterfowl diving for fish, and looking a little enviously at the flats that overlooked the river.