In Italy there are lots of places to visit and if I have to recommended these are the top cities to see:

1.  Venice: it's in northeastern Italy and it's the capital of the Veneto region. Here there aren't car and  there is a famous way of transportation: Gondola. There are numerous attractions in Venice, such as St Mark's Basilica, the Grand Canal, and the Piazza San Marco. 

2.  Florence: It's the capital city of the region of Tuscany;it is known as the "cradle of the Renaissance"  for its monuments, churches, and buildings. The Palazzo Vecchio is the town hall of Florence and also an art museum and Uffizi is one of the best art galleries in the world. There are several different churches such as Santa Maria del Fiore, the Basilica of Santa Maria Novella and the Basilica of Santa Croce. 

3.  Turin: it's the capital of the Piedmont region;Turin is known for it's renaissance, baroque, rococo, neo-classical, and art nouveau architecture. Here you have to visit the Egyptian Museum, the Mole Antonelliana and also the stadium of my favorite team: Juventus. 

4.  Rome: it's the capital of Italy and of the Lazio region.One of the symbols of Rome is the Colosseum, the largest amphitheatre ever built in the Roman Empire. There are also the Roman Forum, the Domus Aurea, the Pantheon, Trajan's Column, Trajan's Market, the Catacombs, the Circus Maximus, the Baths of Caracalla, Castel Sant'Angelo, the Mausoleum of Augustus, the Ara Pacis, the Arch of Constantine and other beautiful monuments.

5.  Milan: it's the capital of Lombardy and it is the main industrial, commercial, and financial centre of Italy. The cathedral is the most important example of Gothic architecture in Italy; near that there is the Galleria Vittorio Emanuele II that is a covered passage with a glass and cast iron roof.