As every year, on 4-5-6 September, starting at a quarter to 1:00 pm (12:45) the extraordinary sacred illuminations of the Pantheon: the Arc of Light and the Square of Light will be seen.
(You can purchase tickets online on the Ministry of Cultural Heritage website)
The Arc of Light perfectly mirrors the masonry arch above the portal, which has a particular horseshoe shape, so that they match perfectly. This happens because the oculus of the dome, through which the rays of the Sun enter, has a diameter of nine meters, and the masonry arch above the portal has the same width, nine meters.
The Square of Light illuminates a marble square on the floor, outside, in front of the portal, in which a circle is inserted.
This happens because the upper part of the portal cuts the circle of light and makes it coincide with the square of the pavement, which has the same width as the portal.
The Pantheon is the masterpiece of the extraordinary construction skills of the Romans, who 1900 years ago were able to design and obtain those luminous «special effects», obviously without computers or artificial intelligence.
The sacred illuminations (hierophanies) had a precise symbolic meaning linked to the cults of Apollo, Diana, Cybele and Jupiter Optimus Maximus. Also the square that contains a circle was a sacred symbol, linked to the Etruscan Templum.
We explain it in detail, along with the construction technique and other wonders of this extraordinary building in the book «Pantheon. Architecture and Light», also in English edition, published by Rirella Editrice.