Pompeii would be my choice. Get up early jump a train, be ready for Napoli, extremely crazy hectic city, but soooo cool. Anyway, Pompeii is so worth it, there is no where else in the world like it. The volcano is still active which makes it a little more interesting!!! It seems as when I was there, most tours left around 10:00 so get there early. If not Pompeii, jump a ferry in Napoli from Porto Beverello, and go to Capri or Ischia islands. I suggest Ischia if you want to really melllllllow out. Capri is fun to go to the Blue Grotto. Google it, and you will see what I am talking about. Happy traveling