The architect of The Pantheon is unknown. It is the best preserved building in all of Rome. It contains a porch, vestibule and main dome. Until 1960, it was the largest dome in the world. The building has many Greek features, because  Emperor Hadrian adored the Greek architecture.

Words that line the frieze say "M·AGRIPPA·L·F·COS·TERTIVM·FECIT" which means Marcus Agrippa, son of Lucius, built during his third consulate.
The interior of the Pantheon is a perfect circle with a diameter of 43 metres. An oculus is situated in the middle of the dome. This oculus measures 8.9 meters in diameter.

The walls of the building are more than 6 metres thick on the bottom level.
Corinthian columns are used in many parts of the Pantheon's structure. The portico has three groups of these columns.
A pediment opens into the massive central rotunda.
Niches where statues once stood line the walls.