Top 10 Facts About the Pantheon

1. It is still the largest unreinforced concrete dome ever built

At about 43.3 m across, the Pantheon's concrete shell has never been surpassed in unreinforced concrete. Florence's Duomo is wider at roughly 45.5 m, but it is a double-shell brick structure with iron and timber chains — a different engineering category, not a bigger version of the same thing.

Book Pantheon Tickets, Tours & Hotels

Avoid buying your ticket on site by booking ahead — compare the official Musei Italiani ticket and the three best-known third-party providers, plus hotels next to Piazza della Rotonda.

Musei Italiani is the official Pantheon ticket seller. Third-party products may be tours, hosted-entry products or bundled services — check the exact inclusions before booking.

2. The oculus is permanently open to the sky

The circular opening at the crown of the dome is about 8.8 m wide and has no glass and no cover. It is the principal architectural light source in the rotunda — the open bronze doors admit daylight too, but the beam that tracks across the interior comes from the oculus. When it rains, water falls in and drains away through the perforated floor. Does it rain inside?

3. Roman concrete can heal its own cracks

MIT researchers reported in 2023 that lime clasts in ancient Roman concrete can react with water entering a crack and redeposit calcium carbonate, sealing it. Their archaeological samples came from Privernum, not from the Pantheon, so this is a property of Roman concrete as a material rather than a measured behaviour of this dome. It is a plausible part of why the building has lasted; it has not been demonstrated inside it.

4. The current Pantheon is almost 1,900 years old

The rotunda you walk into is conventionally dated to around 125 AD, in the Trajanic–Hadrianic period. It replaced earlier buildings on the site — Agrippa's of 27 BC and a Domitianic rebuild — and kept Agrippa's name on the pediment even though he did not build it.

5. The columns were quarried in Egypt

Each of the 16 portico columns is a single granite shaft, about 11.8 m tall, brought from Egypt. The grey shafts are associated with the imperial quarries at Mons Claudianus in the Eastern Desert; the pink and red granite is associated with the Aswan region. They travelled by land to the Nile, downriver, and then by sea to Ostia — an extraordinary logistical operation whichever route each shaft took.

6. It has been a Catholic basilica since 609 AD

Pope Boniface IV consecrated the building as Santa Maria ad Martyres in 609 AD. Continuous Christian use is generally credited as a major factor in its survival, at a time when other pagan temples were being quarried for materials — though it did not protect everything, and its bronze was stripped in later centuries. Mass is still celebrated here.

7. Raphael is buried here

Raphael died in 1520 at 37 and was buried in the Pantheon; early sources, above all Vasari, report that this was his own wish. His tomb is on the left-hand side of the rotunda as you walk clockwise from the doors, under Cardinal Bembo's epitaph. The grave was opened and the remains verified in 1833. More on Raphael's tomb.

8. A sphere fits inside

The interior height and the interior diameter are conventionally given as the same figure, so the rotunda is described as accommodating an inscribed sphere touching the floor and the dome. Individual survey measurements vary slightly, which is why you will see 43.2 m and 43.4 m quoted as well — the design intent of a perfect sphere is not in doubt.

9. Red rose petals fall through the oculus at Pentecost

On Pentecost Sunday, Rome's fire brigade drops thousands of red rose petals through the oculus at the close of the celebration, symbolising the tongues of fire of the Holy Spirit. The exact time follows the officially announced liturgy for that year, and photography is not permitted during the Mass itself. Pentecost and holiday visiting.

10. It is free on the first Sunday of the month

Paid admission arrived in 2023 at €5 and the standard adult ticket is €7 in 2026. Like other Italian state sites, the Pantheon is free for everyone on the first Sunday of each month — expect a substantial queue, since demand concentrates into that single day. Full free-entry rules.

Sources and further reading

• Ministry of Culture — official Pantheon tariff notice (€7 full price effective 1 July 2026) and free-entry categories
• Encyclopaedia Britannica — Pantheon, Rome: structure, dating and history
• MIT News (2023) — hot mixing, lime clasts and self-healing in ancient Roman concrete
• Encyclopaedia Britannica — Raphael: life, work and death
• Basilica di Santa Maria ad Martyres — official liturgical life and Mass schedule

Facts on this page last checked: August 2026. Prices, opening hours and transport routes in Rome change — always confirm with the official source before your visit.

Continue reading about the Pantheon

Frequently Asked Questions

What is the Pantheon most famous for?

Its dome — the largest unreinforced concrete dome ever built, and still unmatched almost 1,900 years later — and for being one of the best-preserved ancient Roman buildings.

How old is the Pantheon?

The building you visit is conventionally dated to the Trajanic–Hadrianic period, around 125 AD, so roughly 1,900 years old.

Who is buried in the Pantheon?

The painter Raphael, the painters Annibale Carracci and Baldassare Peruzzi, and the Italian royal tombs of Victor Emmanuel II, Umberto I and Queen Margherita.

How much does it cost to enter?

€7 for a standard adult ticket, with free categories including all visitors under 18 and the first Sunday of the month.