Nearly nineteen centuries old and still standing, still in use, and still the largest unreinforced concrete dome on earth. Entry has been paid since 2023 — here is how to see it without joining the queue in the piazza.
The inscription on the portico credits Marcus Agrippa, who built the first temple here in 27 BC. The building you see was actually rebuilt under Emperor Hadrian and finished around 125 AD, keeping the original dedication. In 609 it was consecrated as a church, Santa Maria ad Martyres, and that continuous use is the reason it survived almost intact while other temples were quarried for stone.
The dome is 43 metres across and exactly as high as it is wide, so a perfect sphere would fit inside. It is made of unreinforced concrete that gets lighter towards the top, with pumice mixed into the upper layers. At its centre the oculus, nearly nine metres wide, is the only source of light; rain falls straight through it and drains away through small holes in the marble floor. Look for the tomb of the painter Raphael, and those of the first two kings of united Italy.
Tourist entry requires a ticket, while Mass and prayer remain free of charge; visits pause during services. The piazza is busiest from late morning to late afternoon, so arriving early is the best plan. Allow about 45 minutes inside, then stay for a coffee on Piazza della Rotonda. The Pantheon is a short walk from Piazza Navona and the Trevi Fountain, which makes it easy to fit into a centro storico walk.
Build the Pantheon into a centro storico walk with Piazza Navona and the Trevi Fountain, then plan the Colosseum and the Vatican with our complete Rome guide — or let the AI build your day-by-day itinerary.
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