A work born from a dialogue with Florence
When in 1546 Pope Paul III entrusted Michelangelo Buonarroti, then seventy-one years old, with the direction of St Peter's building site, the basilica had been under construction for forty years without a dome. The master's first decision was to return to Bramante's concept: a hemispherical dome on a circular plan, inspired by the Pantheon and by Brunelleschi's model in Florence.
Michelangelo studied the dome of Santa Maria del Fiore carefully — he had seen it as a young man — but devised a taller, more vertical version. He worked on the design until his death on 18 February 1564, leaving behind definitive models and drawings. Construction was completed by Giacomo della Porta in 1590, with one significant modification: the dome was made slightly more pointed than Michelangelo's original hemispherical intention.
Technical data
| Internal diameter | ~42 m |
|---|---|
| Internal height (floor to lantern) | 119 m |
| External height (floor to cross) | 136 m |
| External ribs | 16 |
| Windows in the drum | 16 |
| Total steps (stairs only) | 551 |
| Steps with lift | ~320 |
The double shell
Like Brunelleschi in Florence, Michelangelo designed a double-shell structure: an inner brick shell and an outer one, linked by 16 ribs. The spiral staircase visitors use in the upper portion of the climb runs between the two shells. This arrangement distributes the weight and allows the exterior to rise more gracefully than the inner form alone would permit.
How to climb
Access: from the left nave of the basilica, signposted from inside.
Option 1 — Stairs only (€6): 551 steps from entrance to lantern. The first 231 steps lead through an internal staircase to the rooftop terrace.
Option 2 — Lift + stairs (€8): the lift takes you to the rooftop terrace (saving the first 231 steps). You continue on foot from there.
The route from the terrace onward:
- Rooftop terrace — walk along the top of the nave with an overhead view of the colonnade
- Entry into the drum — circular gallery with close-up views of the great interior mosaics
- Corridor between the shells — narrow passage where you can see the inner dome's curvature from inches away; this is where the 2-metre-tall Latin inscription reads TV ES PETRVS
- External gallery — dome summit with a 360° panorama
The view from the top
From the external walkway you can see:
- St Peter's Square directly below, with the elliptical colonnade
- The Vatican Gardens to the west
- Castel Sant'Angelo to the north-east, 500 m away
- Monte Mario and the Roman hills
- Rome's other domes: Sant'Andrea della Valle, Sant'Ignazio, the Pantheon
In ideal visibility conditions you can make out the sea to the west.
The interior mosaics
The inside of the dome is lined with mosaics executed from designs by Francesco Zucchi and other artists in the late sixteenth and early seventeenth centuries. They depict Christ, the Virgin, the Apostles, the Popes, and — in the lantern — the image of God the Father. The mosaics can be read from the crossing below, but from the drum's inner gallery you stand just a few metres from the faces of the saints.
Practical advice
| Best time | 8:00–9:00 (shorter queues, cooler) |
|---|---|
| Avoid | July–August midday (intense heat between the shells) |
| Not recommended for | Severe claustrophobia or acute vertigo |
| With children | Permitted with adults; no declared age limit |
| Accessibility | No lift beyond the terrace |
| Duration | 45–60 minutes in total |
Visit with a private driver
Reach the Vatican and Michelangelo's dome with a private driver. From your hotel, station or airport — direct and stress-free. Service from €49. → Book at myromedriver.com
Frequently Asked Questions
Is St Peter's dome taller than Florence's? Yes, in total height. Florence's dome is slightly wider (45.5 m vs 42 m), but St Peter's stands taller externally (136 m to the cross vs ~106 m for Florence).
Can you climb in the rain? Yes, access is not suspended in light rain. The external gallery may be closed in strong wind or storms.
What can you see without going all the way up? From the rooftop terrace (reachable by everyone with the lift option) you already enjoy a remarkable view over St Peter's Square and the Vatican Gardens.
Article no. 124 — TIER S — MON-07 San Pietro Type: PRACTICAL Words: ~800