How would you light the inside of a large building if you didn't have electric lights? Why, build it with a hole in the roof to let the sun come in!
That's just what Emperor Hadrian did when he had the Pantheon in Rome remodelled. This temple was designed to be evenly lighted from a 27-foot diameter hole or "oculus" in the center of its huge dome.
When Hadrian decided to significantly enlarge the temple in 118 AD, he took big chances in the design. He decided to make it the first major public building to give the greatest emphasis to its breathtaking marble interior rather than to the outside, as was the case with such earlier temples as the Parthenon, in Greece.
The Pantheon stands more than 140 feet high with a dome 142 feet in diameter. In fact, no building in the world had a dome as large as the Pantheon until the 20th century. To support the huge dome, the walls were built 20 feet thick at the base but become lighter and thinner as they rise toward the center of the dome, which is made of pumice, a very light volcanic rock.
The Pantheon was so named because it was dedicated to all (Pan) the gods (theon). Unlike current American thinking -- which says church and state should remain separate -- to the Romans church was state and state was church. In fact, the title "Pontifex Maximus" (Greatest Bridge Builder) -- which now refers to the Pope of the Roman Catholic Church -- was originally applied to the Roman Emperor in his position as head of the state religion.
The Pantheon is the only building of its time that is still complete and in use. It is used today as a church and museum.
