The Pantheon is a well-preserved ancient Roman temple noted for its large unreinforced concrete dome? Which building is being described?

• A. A contemporary cathedral in Florence
• B. A naturalistic Egyptian portrait
• C. An ancient Roman temple with a massive unreinforced concrete dome
• D. A modern painting by Picasso

Answer: (C)

Recognize the building by its defining combination: an ancient Roman temple in Rome constructed with a massive concrete dome that is unreinforced. The Pantheon fits this description precisely—the great circular drum supports a huge concrete dome with no steel reinforcement, featuring an oculus at the top and a coffered interior. It began as a temple to all gods and was later consecrated as a church, which helps explain its remarkable preservation.

The other choices describe things that are not this architectural feat: a cathedral in Florence is a later Christian structure with different design history; a naturalistic Egyptian portrait is sculpture or a portrait, not a Roman temple; a Picasso painting is a work of modern art, not architecture.