Rain occasionally fall through it but the floor is slanted and drains the water if it manages to hit the floor.
Pantheon roof hole rain.
Rain falling thru the pantheon roof in rome italy.
And at least partially to let out smoke from candles lamps and torches you have to remember that at the time the pantheon was built the only forms of artificial light that existed were candles torches and oil lamps.
The pantheon is the world s oldest building in continuous use.
In practice rain seldom falls inside the dome.
Obviously being open to the elements means it also rains inside the pantheon but a gently sloping floor and 22 well hidden holes help the water to drain away.
However some days are particularly special and that includes pentecost at the pantheon.
Now historians have come up with an intriguing explanation for the feature it was built as a sundial.
This is the one sunday a year when rose petals rain down from the pantheon and it should be on everyone s rome bucket list to experience the special mass at least once.
Air would be sucked in to replace that air from other openings lower down of course.
The hole in the top of the pantheon was to let in light and air.
The huge 30ft hole built into the dome of rome s pantheon has mystified minds for centuries.
These were very inadequate for most situations.
The oculus is small compared to the size of the pantheon and is located at the top of the roof google images and if the building were to be full of people their heated breath and the air heated by their collective bodies will rise pool and create a strong positive outflow through the oculus which would in effect blow the rain away from the opening.
Another beautiful effect takes place at pentecost when rose petals are sprinkled through the oculus after the annual mass.