The 9:4 proportions, the slight curving of the base to make the temple look flat from far, and the metopes are all iconic of the Doric order. All other orders use slenderer proportions and do not have metopes in the frieze.

Ictinus and Callicrates were the architects who designed the Parthenon, but Phidias oversaw the project and was one of its founding fathers as an iconic early Classical architect and sculptor.

Although the Parthenon was a significant form of architecture in the ancient world, it was not Roman, but rather Greek. The Pantheon, located in central Rome, can be considered an example of Roman technological innovation.

The Pantheon was built by Hadrian as a temple to all gods, and is distinguished especially by the "oculus," or "eye," in its roof. The Ara Pacis is an altar built under Augustus. The Colosseum is an arena, and the Pont du Gard, an aqueduct in southern France.

This column was a work of Roman art. It was created in 112 CE as part of a burial chamber. It is located in Rome. The other cultures mentioned also created many similar architectural feats, but they often had other distinctive characteristics.

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Trajan was a Roman emperor who ruled from 98-117 CE. This column was placed outside of the Forum of Trajan, where he was buried. The inscriptions on the column, as well as the surrounding buildings and structures, tell the stories of his life and success. (The others mentioned are also Roman emperors from different time periods.)

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Roman triumphal columns were massive structures erected in the city of Rome to celebrate massive victories in battle against enemies. These arches were huge structures with minute details of the battle's events and signifiers of the people who were defeated. These triumphal arches were used as models for many later arches in European history, such as the Arc de Triomphe in Paris.

Bas-relief a very ancient artistic form. Bas-relief, from the French for "low relief," is a sculpture that leaves a background in the medium, carving only a portion of the front of the image into the stone being used. Bas-relief was first developed by the Ancient Egyptians, and widely used in Classical Greece and Rome.

Both Kouros (c. 600 BCE) and Dying Warrior from the Temple of Aphaia (500-490 BCE) are works of Archaic Greek sculpture. Kritios Boy is from 480 BCE and is an early work of the Classical period. Laocoon and His Sons (c. first century CE) is from the late Hellenistic period.

The Ionic order was named after the region of Ionia, a smattering of islands between Greece and Asia Minor (modern day Turkey), which were settled by Greeks in roughly the seventh century BCE. While the Ionians were there, they adapted Greek architecture into a simpler form, with more slender columns and less ostentatious ornamentation. This architectural form spread through mainland Greece, with the Temple of Athena Nike, at the entrance to the Acropolis in Athens, being an early example and the first Ionic building on the Acropolis.