Like no other city in Europe or in fact the world. Be sure to visit the Colosseum, the Roman Forum, St Peter’s Basilica, the Trevi Fountain, the Pantheon, and of course the Spanish Steps. Aside from that, be sure to wander around Rome on foot and explore it’s endless alleyways and boutique shops, it will be sure to keep you busy for at least a few days.
I would recommend no less than 4 days to explore Rome.