What architectural feature is present on all four sides of the Parthenon?

The architectural feature present on all four sides of the Parthenon is the Doric frieze. The Parthenon, built as a temple dedicated to the goddess Athena, exemplifies the classical Doric order, which is characterized by its simplicity and strength. The Doric frieze consists of alternating triglyphs (three vertical grooves) and metopes (plain or decorated panels), creating a rhythm and pattern that enhances the structure's overall aesthetic.

In the context of the Parthenon, the use of the Doric frieze contributes to the iconic nature of the building and underscores its grandeur as a symbol of Athenian democracy and culture. While other styles and features are significant to the Parthenon's design—such as the Ionic columns seen on the temple's roof and the application of visual corrections in its proportions—the Doric frieze is a defining element consistently found on all sides of the structure. This underscores the Parthenon’s adherence to the principles of classical architecture, where symmetry, harmony, and proportion were paramount.