how many times will you spend in Rome?
If you’ve 3 or 4 days, you’ve to see the classical things (san pietro, musei vaticani, campidoglio, colosseo, fori imperiali, piazza di spagna, piazza del popolo, villa borghese, piazza navona, campo dei fiori, trastevere etc.), but if you spend a week there, I suggest you to visit the gianicolo hill (with the “fontanone” and the church of “san pietro in montorio), the garden of oranges and the aventino hill, the “centrale montemartini” (it’s a museum with a lot of beautiful roman sculptures), caracalla’s thermal baths, and something of contemporary architecture like the auditorium or the MAXXI