If you find yourself planning day excursions while on vacation in Italy, I highly recommend Cinque Terre. Cinque Terre is a string of five villages on the Italian coastline that easily has enough to fill your day.
My suggestion is to take the train to the furthest village and then make your way back. If you’re feeling adventurous, there’s a hiking trail to take you from village to village, but be sure to wear comfortable shoes.
We ended our day with a boat tour of all five islands to get a different perspective of the area, and it was breathtaking.