We are torn between an all day bus trip to Pompeii (including a short hike at Vesuvius) and a shorter day trip to Hadrian's Villa & villa d'Este in Tivoli. I am concerned that Pompeii is too long a trip when we only have 4 days in Rome, but is Pompeii just so much more spectacular than Tivoli that it is worth it? We are history and archaeology lovers, so both of these appeal - matter of fact my son wants to do both, but I think that won't leave us any time in Rome! Any thoughts from people who've been to Hadrian's Villa? Or is Ostia Antica a shorter trip and good substitute for Pompeii?