The Pantheon

The Pantheon is the best-preserved building of ancient Rome and still feels impossible: a concrete dome wider than a football pitch’s width, unreinforced, open to the sky through its nine-metre oculus. Rain falls straight through onto the marble floor, and drains built for it 1,900 years ago still work.

• The oculus, the building’s only light source, moving a spotlight across the coffers all day.
• The dome itself, stand at the centre and read the geometry; the height equals the diameter.
• Raphael’s tomb, the painter rests in a side niche, with kings for company.
• The bronze doors, ancient, enormous, and still swinging on their hinges.

Go at opening on arrival day, jetlag makes early easy, or in the last entry hour. Midday brings the strongest oculus beam and the thickest crowds together; pick which matters more.

It sits in the walkable heart of the centro storico, minutes from Piazza Navona and the Trevi Fountain. Entry is ticketed now; book online and walk past the piazza queue.