The Métro is Rome's subway system
Rome's Metro (which is short for "Metropolitana,"which is the Italian term for "underground train,"which is British for "subway")—whih uses the same tickets and passes as the bus—is a good idea that turns out to be fairly useless.
The main reason for this is that it isn't very extensive—every time workers dig new tunnels, they run across ancient ruins and have to stop so archaeologists can putter about.
The city has only two lines (the orange "A" and the blue "B") that etch a rough X on the city map, with Stazione Termini train station at the intersection.
- Line A runs from Viale Aurelia, past Cipro–Musei Vaticani (the new Vatican Museums stop) and Ottaviano–San Pietro (a dozen blocks from St. Peter's), and makes stops such as Flaminia (near Piazza del Popolo), Spagna (at the Spanish Steps), Termini, and San Giovanni (Rome's cathedral).
- Line B is most useful to shuttle you quickly from Termini to stops such as Colosseo (the Colosseum), Circo Massimo (the Circus Maximus), and Piramide (at the Tiburtina train station, near Testaccio).
(So I lied. There is also a Line C. However, (a) it still being built, (b) so far it only extends from the extreme eastern suburbs in to a few stations just inside the ring road, and (c) even once it is finally completed all the way to Termini, it will not pass a single sight of interest to tourists, so for visitor purposes it is useless.)