"The Pantheon is a former Roman temple and, since 609 AD, a Catholic church in Rome, Italy, on the site of an earlier temple commissioned by Marcus Agrippa during the reign of Augustus. It was rebuilt by the emperor Hadrian and probably dedicated c. 126 AD." Wikipedia.
Just a few photos of the facade taken early one morning as I passed by. Top tip: Go early in the day, be first in the queue, later in the day it is a zoo with thousands queueing to get in.
Click on any image to see a larger version.