The Pantheon in Rome was commissioned by Marcus Agrippa, the general and friend of the Emperor Augustus. It was built as a temple honoring all the gods of ancient Rome; it is now a Roman Catholic church. The roof of the temple consists of a dome which features a circular hole at the top to allow the light of the heavens to illuminate the interior space. The dome is constructed of concrete and weighs 4,999 tons. Geometrically, the dome consists of a section of a perfect sphere with a diameter of 142 feet. This is the exact height from the floor of the interior to the hole in the top of the dome, meaning that if the dome were to be extended as a sphere, the bottom would rest on the floor. The floor is built on a slight incline to allow rain water to drain away.
The Pantheon
Piazza della Rotonda
Rome 186, Italy
011-39-06-6830-0230
In the 15th century, the artist and architect Brunelleschi won the competition to design and build the dome over the newly constructed cathedral in Florence. Many people believed that a dome of such a great size could not be built, but Brunelleschi, a skilled mathematician and engineer, succeeded. The dome features two layers, an octagonal inner layer constructed of light materials and an outer layer constructed of heavier, weather-resistant brick. The inner layer provided a base from which workers could construct the outer layer. The bricks used to build the dome are laid in a herringbone pattern. Laying the bricks in this way spreads the weight of the bricks onto the vertical stone ribs framing the dome, allowing the mortar holding the bricks together to set. The dome spans 144 feet; when it was constructed, it was the largest dome to be built since that of the Pantheon.
Cathedral of Santa Maria del Fiore
Piazza Duomo 17 - 50122
Florence, Italy
011-39-05-521-5380
The Capitol Building in Washington, D.C., is the home of the U.S. Congress. The building features a dome designed by Thomas Walter in 1845; construction of this dome was completed in 1866. The rotunda consists of an inner dome and an outer dome. The interior dome is 180 feet high, while the exterior dome is over a hundred feet higher at 288 feet, including the "Statue of Freedom," which stands at the top. More than 4,400 tons of iron were used in the construction of the Capitol dome, which is surrounded with 36 decorative stone columns.
The Capitol Building
Capitol Hill
E. Capitol St. and 1st St.
Washington, DC 20510
202-225-6827