14. The building is circular with a
portico of huge granite
columns under a pediment
opening into the rotunda
A rotunda (from Latin
rotundus) is any building
with a circular ground
plan, often covered by a
dome
17. The rotunda is under a coffered, concrete dome, with a
central opening (oculus) to the sky. Almost two
thousand years after it was built, the Pantheon's dome
is still the world's largest unreinforced concrete dome.
Oculus