Overview
Religious Significance
Delphi was revered as the omphalos (navel) of the world, the central point where two eagles sent by Zeus met. The sanctuary was dedicated to Apollo, who was believed to have slain the serpent Python on the site, establishing purification rites that evolved into the prophetic cult. The Pythian Games, held every four years, were second only to the Olympics and included athletic and musical contests.
Architecture and Monuments
The Sacred Way led from the sanctuary entrance up to the Temple of Apollo, past treasuries erected by various Greek city-states to display votive offerings. Notable structures include the Athenian Treasury, the Stoa of the Athenians, and the Temple of Apollo itself, which housed the adyton where the oracle sat. Higher up lie the theater, stadium, and the Castalian Spring, used for ritual purification.

The drainage system at the Sanctuary of Apollo in Delphi on October 4, 2020 | George E. Koronaios (CC BY-SA 4.0)
"Know thyself."
— Inscription at the Temple of Apollo, Delphi (attributed to the Seven Sages of Greece)
The Oracle and Pythia
The Pythia, a priestess over 50 years old, entered a trance-like state—perhaps induced by geological gases—and uttered obscure sounds that priests interpreted as prophecies. Our understanding of the process relies on ancient authors like Plutarch, who served as a priest at Delphi, and on geological studies suggesting ethylene emissions from a fault line beneath the temple.

At the Theatre of Delphi (Sanctuary of Apollo) on October 4, 2020 | George E. Koronaios (CC BY-SA 4.0)
Discovery and Excavation
The modern village of Kastri was built atop the ancient remains. After an earthquake in 1870 exposed some ruins, the French School at Athens negotiated relocation of the village and began systematic excavations in 1892 under Théophile Homolle. The so-called "Great Excavation" lasted until 1903, uncovering the sanctuary, the stadium, and the Charioteer of Delphi.
Decline and Legacy
Delphi declined after the Roman period, and the oracle was silenced by Theodosius I in 393 CE. The site was gradually abandoned and buried until its rediscovery. Today, it is a UNESCO World Heritage site, drawing scholars and tourists alike, and continues to yield insights through ongoing archaeological and geological research.
