My alltime favourite place in Italy, even beats Rome (IMO)!!! Beautiful medieval town with well preserved medieval structure and buildings, sturdy town-wall that is visible from afar to the coming visitors. Perched on a hilltop, the city is crowning the whole surroundings. Narrow streets with steep steps and high towers and buildings and a magnificent cathedral guarding over the remains of St. Francisco, with beautiful murals from Giotto.
If you are already in the neighbourhood, it is worth visiting the nearby church of San Damiano/Gimiano, which, according to the legend, was built by the very hands of the saint himself.