When Emperor Hadrian decided to build a monument reflecting Rome's power, he constructed the Pantheon in Rome with an enormous dome larger than anything previously built. At 142 feet in diameter, the dome was supported by innovations like coffers to reduce weight and an oculus opening at the top. The impressive and innovative design of the Pantheon's dome allowed it to remain the world's largest dome for over 1,000 years.

1. PANTHEON
When Roman Emperor Hadrian decided to
build a monument to reflect the power of his
empire, he built a dome -- but not just any
dome. Hadrian constructed a building out of
bricks and concrete with a dome that was
bigger and more extraordinary than
anything anyone had ever seen before. The
enormous building, called the Pantheon, was
built as a temple to all the Roman gods
almost 2,000 years ago. Pantheon is a Greek
word meaning "to honour all Gods”. It still
exists today, almost entirely in its original
form.
The Pantheon is remarkable for its size, its
construction, and its design. The enormous
dome stretches 142 feet in diameter; that's
the same as the distance from the Statue of
Liberty's sandals to her torch. Given the

2. dome's size and weight, Hadrian's engineers
had to find ways to lighten the heavy
structure.
They scooped out 140 waffle-like
depressions, called coffers, in five rows
around the dome's base to eliminate some
masonry and reduce the dome's weight.
They also carved an opening, called an
oculus, at the top of the dome, which
reduced some mass and created a daily light
show for which the Pantheon is famous. The
oculus, or "eye" of the dome, is 27 feet wide -
- five teenagers could stretch across the hole.
At its base, the dome is 23 feet thick, but
only two feet thick at the rim of the oculus
The result was an impossibly huge dome;
one that would remain the world's largest
for 1,300 years.

3. Measurements:
Foundation: 24’ thick at base and steps to
21’ at ground level.
Rotunda: concrete, 20’ thick; 142’
diameter.
Oculus: concrete: 7.5’ thick; 27’ diameter.
Interior Columns: 3’ diameter, 29’ tall
topped with a Corinthian capital of 4’
totalling 32’ 9" tall, 25 tons each.
Portico: 16 granite columns 39’ tall, 5’
diameter, 60 tons each.

4. THE END