But with some 20,000 visitors a day passing through its museums, and many more visiting St Peter’s Square, it’s wise to be well organised about a visit. Here are six highlights and how to enjoy them.
1. St Peter’s Basilica
The world’s largest church is a Renaissance masterpiece with an ornate, mostly baroque interior, filled with works by artists such as Michelangelo, Bernini and Giotto.
There’s only one entrance, on the piazza’s right-hand side. Arrive soon after opening at 7am if you want to avoid long queues. Dress appropriately, because you won’t be allowed into the basilica (or Vatican Museums) with bare knees or shoulders.
Entry is free, but once inside, the treasury, ascent of the dome and descent into the necropolis are ticketed. You must be over 15 years old and apply online well in advance to visit the necropolis.
2. Vatican Museums
Housed in the papal palace, the many museums of this complex bring together the world’s richest art collection, crammed with paintings from the likes of Raphael and Leonardo da Vinci, as well as ancient Greek and Roman statues, Etruscan pottery, tapestries, manuscripts and much more.
Don comfortable walking shoes and plan your route in advance (or engage a guide) to see whichever parts interest you most, because you won’t see it all.
Ticket queues can be hours long, though shortest over lunchtimes and on Wednesday mornings. Best book online for a modest surcharge. Entrance is free the last Sunday morning of each month.
3. Sistine Chapel
This chapel, gloriously painted by Michelangelo, is adjacent and connected to St Peter’s Basilica, but can only be accessed through the Vatican Museums. Ignore ticket fraudsters in the piazza who claim otherwise.
This hugely popular focus of the museums is often very crowded; again, lunchtimes or Wednesday mornings (when the Pope gives audiences) are best. The chapel also has very limited Sunday opening hours.
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4. Vatican Gardens
The least-visited part of the Vatican is its lush and surprisingly large gardens, which feature the ruins of ancient fortifications, splashing fountains, huge oak trees and plenty of flowerbeds.
Tours take two hours and must be booked in advance online. Tickets must then be picked up a couple of days prior to your tour at the tourist office on the left-hand side of St Peter’s Square. You can also get a glimpse of the gardens from the Vatican Museums.
5. Castel Sant’Angelo
Though technically just beyond the Vatican’s borders, this fortress on the Tiber River has been a papal residence and prison since the 14th century and contains the Renaissance-era apartments of the infamous Borgias.
Entry is free on the first Sunday of the month. On summer evenings there are occasional openings of Il Passetto, a tunnel linking the fort with St Peter’s Basilica.
6. The Pope
Pope Francis gives a public audience every Wednesday morning around 10:30am, usually in the Hall of Audiences or (especially in summer) in St Peter’s Square, so check the Vatican’s website.
Arrive a couple of hours in advance to get through security and nab a good front seat. Attendance is free but you must have a ticket, which you can order online or get from the office of the Papal Prefecture, open only Monday mornings and Tuesdays near the basilica’s Bronze Doors.
The pope also appears in his study window above the piazza at noon on Sunday (except in summer) for a blessing.