The enigma of the Pantheon
Divine architecture, plays of light, and ancient legends. How the oculus has dictated time for millennia.
Rebuilt by Emperor Hadrian around 125 AD, the Pantheon's dome is still the largest unreinforced concrete dome in the world: 43.3 metres wide.
The oculus is the only source of light. On 21 April, Rome's birthday, at noon the beam falls exactly on the entrance door.
And when it rains? Small holes in the marble floor drain the water — a 2,000-year-old solution that still works.