The city walls of Cittadella are a rare example of medieval means of defense with a still practicable, perfectly preserved parapet walk. As a matter of fact it is one of the most beautiful means of defense in Europe.The walls’ circumference is 1461 meters, its height 14 meters, the keeps reach a height of up to 30 meters. The average thickness of the walls is 2,10 meters. The four gates, 450 meters equidistant from each other, lie approximately along the four cardinal points. The surrounding walls are characterised by 4 keeps, 12 towers and 16 turrets. The distance between them is 40 metres; each of these sections is crowned by so called “Guelph” (rectangular) merlons; in some parts there are also “Ghibellini” merlons (they look like dovetails) because of later renovations. The surrounding walls are virtually without foundation being only supported by the embankments derived from the excavation of the moat.The moat runs all around the walls and is fed by spring water. It once was twice as deep and twice as large creating a rich habitat for fishes. The moat served as defense and was crossed by wooden drawbridges which later on were substituted by stone bridges. The construction of the walls has involved the manpower of many workers for many years. The first defense structures, the accesses and the moat, were made out of wood and earth. Only later was the whole complex rebuilt in stone. In a first phase, the four entrances were built and nearly all the towers connected by a low wall; in a second construction phase the wall was heightened and completed with merlons and bows.The recent restoration and safeguarding of the ancient Parapet Walk allows visitors to admire the town from favoured viewpoints. From on high you will notice that the internal spaces are arranged on a geometrical chessboard-shaped system of Roman origin, based on the two main axes that connect the four gates lying more or less along the cardinal points:southbound to Padova, westbound to Vicenza, northbound to Bassano and eastbound to Treviso.The breach in the wall of the northwestern quadrant is crossed over by a footbridge in order to continue the parapet walk.