Discover Treviso City Walls

The design is the point. Medieval walls were tall and thin, built against ladders and siege towers; cannon made them a liability. Fra Giocondo's walls are low, immensely thick and backed with earth, so shot buries itself rather than shattering masonry.

Projecting bastions at intervals are angled so that defenders on one can sweep the face of the next -- crossfire along the ditch, with no blind spots at the base of the wall. This is the trace italienne, and Treviso is an unusually early and unusually complete example of it.

A wet ditch fed from the rivers runs outside, and the whole circuit was engineered together with the waterways rather than laid on top of them.

The three surviving gates are ceremonial as well as defensive: Porta San Tomaso in particular is a piece of Venetian display architecture, with the lion of St Mark above the arch.