Italy is known for many things, but ranked high among them is the remarkable architecture of the edifices that fill her cities and towns. From great cathedrals to small churches, railway stations to public buildings, Italy shows off the skills of her sons and daughters.
Once the great basilicas were sculpted a stone at a time. Each saint, altar, and gargoyle represented years of work, sometimes by teams of crafts-people. All that fantastic work, which continues to awe visitors and residents today, began with the passion of ancient Romans for majesty in their city. To accomplish their visions, they had to do more than sketch and build. They first had to devise the tools and materials to make their ideas come to life. The invention of concrete made much of their best work possible.
Rome’s great advances in architecture and engineering as perhaps best illustrated by the astounding dome of the circular Pantheon.
Based upon Archimedes’ mathematical revelations, the Pantheon is a sphere within a cube. The world’s largest unsupported concrete dome, it was achieved by gradually tapering the thickness of the dome’s shell as it rose, requiring complex mathematical calculations to perfect both the interior and exterior surfaces.
The magnificent, unsupported dome is 43.28 meters high, and the width of the base is also 43.28 meters. A sphere of that diameter, if resting on the floor, would therefore touch all the interior surfaces of the dome perfectly. That design has given it the strength to stand in continuous use without significant maintenance since the Emperor Hadrian ordered its construction in 126 CE. It might have been damaged or destroyed during the intervening years, but one of the last emperors, ruling from Constantinople as the Western Empire collapsed, found no use for it, and donated it to the Catholic Church. It thereby escaped the fate of the Coloseo and many of the temples of the Forum, which were robbed of marble and stone for private uses.
Pantheon means “all the gods.” The only light within the building enters through a circular hole at the top of the dome, called an occulus. As a result, a single shaft of light enters with the sun, and sweeps across the floor each day, but on an ever-changing path that moves with the seasons, thereby inscribing a horizontal figure-eight on the floor. You may find that same device, known as an analemma, imprinted on your modern globe.
We stood in that single shaft of light, and in an instant, all the rest of the interior disappeared into the shadows. It was like being on a stage, unable to see the audience beyond the footlights. Stepping out of the sun, we watched dust motes drift in its glare as the rest of the interior came slowly back into focus.
The Pantheon remains one of the most remarkably simple and beautiful structures in the world. Standing within that space listening to the echoing footfalls of visitors and the muffled voices that reverberate from the perfect symmetry above is nothing less than awe-inspiring.