The Basilica di San Pietro, better known to many as St Peter’s, is the principal shrine of the Catholic Church, built on the site of St Peter’s tomb, and worked on by the greatest Italian architects of the sixteenth and seventeenth centuries. One of the channels on the right side of the piazza funnels you into the basilica (the other two lead to the underground grottoes or the ascent to the dome). Bear in mind that whichever you opt for first, you need to be properly dressed to enter, which means no bare knees or shoulders – a rule that is very strictly enforced.

The interior

Going straight into the church, the first thing you see is Michelangelo’s graceful Pietà on the right, completed when he was just 24. Following an attack by a vandal, it sits behind glass, strangely remote from the life of the rest of the building. Further into the church, the dome is breathtakingly imposing, rising high above the supposed site of St Peter’s tomb. With a diameter of 41.5m it is Rome’s largest dome, supported by four enormous piers, decorated with reliefs depicting the basilica’s “major relics”: St Veronica’s handkerchief, which was used to wipe the face of Christ; the lance of St Longinus, which pierced Christ’s side; and a piece of the True Cross. On the right side of the nave, the bronze statue of St Peter is another of the most venerated monuments in the basilica, its right foot polished smooth by the attentions of pilgrims. Bronze was also the material used in Bernini’s wild, spiralling baldacchino, a massive 26m high, cast out of 927 tonnes of metal removed from the Pantheon roof in 1633. Bernini’s feverish sculpting decorates the apse, too, his bronze Cattedra enclosing the chair of St Peter, though more interesting is his monument to Alexander VII in the south transept, with its winged skeleton struggling underneath the heavy marble drapes, upon which the Chigi pope is kneeling in prayer.

The treasury and grottoes

An entrance off the aisle leads to the treasury (daily: April–Sept 9am–6.15pm; Oct–March 9am–5.15pm; €5), which has among many riches the late fifteenth-century bronze tomb of Pope Sixtus IV by Pollaiuolo.You can opt to visit the grottoes (daily: April–Sept 8am–6pm; Oct–March 7am–5pm), emerging in the basilica at the central crossing. They are not the legenendary burial spot of St Peter himself (that’s something different) but are in fact where a good number of later popes are buried, including the last one, John Paul II.

The roof and dome

Also accessible by one of three main outside entrances, the ascent to the roof and dome is well worth making. The views from the gallery around the interior of the dome give you a sense of the enormity of the church, and from there you can make the (challenging) ascent to the lantern at the top of the dome, from which the views over the city are as glorious as you’d expect.