Aptly named the eternal city, modern Rome has an ancient city that is 2000 years old right beneath it, well preserved and difficult to excavate without causing trouble for the millions of Italians currently living in Rome. Thus, there are no metro lines at the heart of the city, and the nearest metro lines are located at the outskirts of the city centre. Rome is a largest city that I have walked about so far and rather taxing. There are two free walking tours a day, one at 10am and 4pm daily at the Spanish steps. Each takes about 2 hours, the first one brings you to Vatican City, the second one to the Colosseum. You can easily spend 2-3 days in Rome visiting various places like the Colosseum, Pantheon, Vatican City, several Piazzas, the ancient walking bridge (so ancient that no cars can go on it), basilicas, Trevi Fountain, Castel Sant'Angelo, the Forum, Palatine hills, etc. The best pasta and gelato are also found in Rome, so do a good search to know which ones to go to.
