With visa-free access to 176 countries, Germany still has the most powerful passport in the world.
It has retained the No. 1 position in an annual travel freedom ranking, despite losing visa-free admission to one country. Sweden remains in 2nd place with 175 countries, and Denmark, Italy, Spain, and the USA rank 3rd, with their nationals enjoying access to 174 countries without a visa.
You could easily find enough attractions to spend a week in each of these Italian cities, but you can see the highlights of all 3 in a well-planned week.