Lucca

Lucca needs 1 day: its complete Renaissance walls, turned into a 4.2 km elevated promenade walkable or bikeable, fully encircle the old town. April-October is best. It's cheaper than Florence or Pisa, just 30 minutes away by train. Unlike almost any other Italian city, it was never conquered or sacked for centuries thanks to those walls -among the best preserved in Europe-, which allowed it to remain an independent republic until the 19th century and keep a street and tower layout that's virtually intact.