Venice - Rialto Bridge on Grand Canal
Any country that has even one city of the same world-class attraction as these should consider itself lucky.
The reason for this is historical.
For a great part of its history, Italy has not been a unified state, like England or France, but a myriad of city-states in the Middle Ages (the so-called 'comuni'), and then a collection of states, among which the Grand Duchy of Tuscany, the Kingdom of Savoy in the west, the Kingdom of the Two Sicilies in the south and the Vatican State, which used to include most of central Italy.
This means that many of its cities developed to the level of capital cities and even commanded great empires: just think of Venice, the Serenissima Repubblica di San Marco, for example. Not to mention Rome, the city (urbs in Latin) par excellence.
Most of the major cities (and indeed towns) in Italy are of Roman origin, and have subsequently been rebuilt in the Middle Ages on the Roman foundations. Therefore their centre is Medieval (in Italian it's called "centro storico" [pron. chentro]), and its squares and particularly its narrow, pavement-less streets are unsuitable to cars and modern traffic. For this reason, following the rise of the environmentalist and conservationist movements in the 1970s and '80s, Italian town and city centres are often closed to motorized traffic: they have become an "oasi pedonale" (for pedestrians only).
As far as towns are concerned, in the countryside towns often have two parts: the old town was built on a hilltop to protect it from invaders, pirates, highwaymen or any assailants of the time, whereas the new, modern town has spread at the foot of the same hill, for better communication and connection to the road networks.
If you're going to Italy in the summer, beware that one of the greatest national and religious holidays of the year falls on the 15th of August, the Feast of the Virgin Mary's Assumption, which is the Roman Catholic calendar's main festivity of the Virgin Mary. Italians call this day "Ferragosto". Holiday resorts like seaside places will be lively and indeed crowded, but cities like Rome and Florence will be almost empty in mid-August (which might be a good thing for tourists), and many shops and businesses are shut on 15 August.
Italian cities can be chaotic, especially southern cities like Naples. Rome as well has some traffic problems. But then, what big city has not got them?
Italian Mini Dictionary
Roma = Rome * Firenze = Florence * Venezia = Venice
Napoli = Naples * Genova = Genoa * Milano = Milan * Torino = Turin