PALMANOVA, as already mentioned, built as a fortress city and a bulwark in insecure medieval times.
Restructured by Napoleon Bonaparte in eighteenth century, close to my home, is always worth a trip and nice "Cafè Macciato".
A beautiful cathedral dominates the centered parade ground, where several replicas of ancient construction machines are to be seen. (pls see pics)
The whole city is surrounded by several mounds and a moat, which could be dammed up to a water level of about five meters to repel advancing enemies.
Additionally were lots of tunnels, from which some were "contromine", means to lure the enemy into, whereupon this tunnel was partially blown up on them.
A national monument, worth to be checked out.