We will be in Rome in early December. We will have only two full days for sightseeing. We have been to Rome a few times previously, but we have never visited Hadrian's Villa or Ostia Antica. Given our limited time, I'm thinking that it could be too much to do day trips to both of these places in such a short visit.
Given that we should probably choose just one, which of these two places would you choose to visit?
Thanks.