050 Italy - Rome - The Pantheon Dome

The Pantheon Dome

The Pantheon may well be the first building from Classical architecture where the interior is deliberately made to outshine the exterior. The circular part of the building or rotunda was entranced via two bronze doors measuring 39 x 26 ft (those of today are ancient but not original). The rotunda measures 142 ft in diameter which is exactly the maximum height of the dome, itself a perfect hemisphere. At the very top of the dome is an opening to the sky (oculus) which is 29 ft in diameter and has a decorative bronze sheet frieze. The dome is made from a light tufa and scoria (a type of pumice) mix of concrete (caementa) and its interior is further lightened by five rings of 28 coffers which reduce in size as they rise towards the centre of the dome.

The Pantheon dome is still the largest unreinforced solid concrete dome in the world!