Pantheon
The best-preserved building of ancient Rome — a 2nd-century temple with the largest unreinforced concrete dome ever built, still standing 1,900 years later. A modest entry fee since 2023, always astonishing, and busiest around the oculus at midday when a single shaft of light crosses the floor.
As a working church — the Basilica di Santa Maria ad Martyres — the Pantheon holds Mass on Saturday evenings and Sunday mornings, when general visiting is more limited. The oculus at the top of the dome has no glass at all, so rain falls straight through onto the floor below, which has a barely perceptible slope and a set of drainage holes built into the original design specifically to cope with it — a piece of engineering that's been quietly working for nineteen centuries.
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Agrippa built the first Pantheon in 27 BC as a temple to all the gods, which is what the name means. It burned down, and what stands today is Hadrian's rebuild from around 126 AD — the best-preserved building in ancient Rome and, for most of its history, free to walk into.
That changed in 2023, when paid entry began for the first time in the building's roughly nineteen-century existence. Romans have not entirely forgiven it.
The dome nobody's fully explained
The dome is the largest unreinforced concrete dome ever built, and it has never been surpassed — not by anything built since, with steel or without it. The concrete gets progressively lighter as it rises, mixed with pumice near the top instead of heavier aggregate, and the whole thing is thinner at the crown than at the base. How Roman engineers calculated that so precisely, with no modern materials science to draw on, is still argued over by structural historians.
At the very top is the oculus, a 9-metre circular opening that is the building's only light source and has no glass in it at all. Rain falls straight through onto the marble floor below, which slopes almost imperceptibly toward a set of drainage holes built into the original design specifically to handle it — a piece of Roman plumbing quietly doing its job for nineteen hundred years.
What the ticket actually costs, and who's exempt
General admission runs a modest fee, bookable online or at the door, and the building still functions as a working church — the Basilica di Santa Maria ad Martyres — which means Mass on Saturday evenings and Sunday mornings, when general visiting is restricted. EU residents under eighteen, and a handful of other categories, enter free; check the official schedule before assuming.
The oculus at midday is the moment everyone comes for: a single shaft of light moving across the floor and up the far wall as the sun crosses overhead. It's most dramatic around the spring and autumn equinoxes, when the light lines up squarely with the entrance.
Who's actually buried here
Raphael's tomb is here, at his own request, in a niche he designed to hold his sarcophagus. So are two Italian kings, Vittorio Emanuele II and Umberto I, along with Umberto's queen — a detail that surprises visitors who expect a purely ancient building and get a nineteenth-century royal tomb instead.
The bronze doors at the entrance are original, or close to it — 4.5 metres tall, cast in the second century, and still swinging on their original hinges after roughly eighteen hundred years of daily use.
Pantheon: common questions
01Is the Pantheon free to enter?
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No, not since 2023. A general admission fee applies to most visitors, bookable online in advance or paid at the door. EU residents under eighteen and some other categories are exempt — check the official ticketing site for the current list.
02How do I avoid the crowds at the Pantheon?
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Go right at opening, around nine, before tour groups arrive. Midday is the busiest stretch, partly because that's also when the oculus effect is most dramatic and everyone knows it.
03Why does rain fall inside the Pantheon?
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The oculus at the top of the dome has never had glass — it's an open hole, 9 metres across. Rain falls straight onto the floor, which has a slight slope and drainage holes built into the original ancient design to cope with exactly that.
04Who is buried in the Pantheon?
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The painter Raphael, in a tomb he designed himself, along with two Italian kings — Vittorio Emanuele II and Umberto I — and Umberto's queen, Margherita, after whom the pizza is popularly said to be named.