The Parthenon in Athens, dedicated to Athena, is the most celebrated example of the Doric order. Built between 447 and 432 BCE by Ictinus and Callicrates, it showcases exquisite proportions based on the ratio 4:9, extensive sculptural decoration under Phidias, and sophisticated optical refinements.

The Pantheon in Rome, completed around 125 CE under Emperor Hadrian, remains one of the greatest architectural achievements in history. Its massive, unreinforced concrete dome—the largest in the world for over a millennium—features a central oculus and perfectly spherical interior proportions (the interior height equals its diameter).

An ancient rectangular stone building features a continuous colonnade surrounding a central room. The columns have a sturdy, fluted shaft with an unadorned, saucer-shaped capital and display a slight convex swelling.