Although technically a separate state from Italy, the centre of the Catholic church is a central part of the Roman experience.
It's also a hotspot for pickpockets, so be careful - in 2005, there were 472 criminal cases, most of which were to do with theft. And that's only the ones that got to court. (In 2005 the Vatican had a population of just 492, plus approximately eighteen million visitors.)
Things to see
From St Peter's Square - which is suitably awe-inspiring - you can access the basilica itself. There are usually queues to get in but, being a church, it's free. Remember that like all churches in Rome, you will need to dress appropriately. Both sexes should make sure their knees and shoulders are covered. It's also possible to make a special ascent of the inside of the dome, which costs €5.
The Vatican museums are described by The Rough Guide to Rome as 'quite simply, the largest, richest, most compelling and perhaps most exhausting museum complex in the world.' Entry is €12/€8. The Vatican Museums are closed on sundays, but open on the last sunday of the month, when admission is free.
Visiting the Vatican City
To reach St Peter's Square on foot, cross the Tiber either at Ponte Vittorio Emanuele II, or at Ponte Sant Angelo which will take you to Castel Sant'Angelo. From either bridge, head down Via della Conciliazione. The Basilica is accessible from the square; to reach the museums you will have to walk around the outside of the Vatican to the entrance on Viale Vaticano. The nearest metro stations for the museums are Ottaviano and Cipri (Musei Vaticani) on Linea A.
The official website of the Vatican City is at Vatican.va.