Pantheon
The Pantheon from Greek: Πάνθεον, an adjective meaning "to every god") is a building in Rome, Italy, commissioned by Marcus Agrippa as a temple to all the gods of Ancient Rome, and rebuilt by Emperor Hadrian in about 126 AD.
Almost two thousand years after it was built, the Pantheon's dome is still the world's largest unreinforced concrete dome. The height to the oculus and the diameter of the interior circle are the same, 43.3 metres (142 ft).
from Wikipedia
