A large rectangular open space in the heart of the old town, the Roman Forum is the spine on which Zadar grew. Today it is mostly grass and broken paving — the bases of temple columns, fragments of inscribed altars, the foundations of a triumphal arch — but the scale of it is still impressive, and the surrounding monuments (St Donatus, the cathedral, St Mary's) all face onto it.
The site is open and free to walk, and is at its best in early morning or late evening when the sun is low across the broken stone. Look out for the lone standing column at the north end — a survivor of two thousand years of city life.