ancient town and seat of the most important Greek (ancient Greek civilization) temple and oracle of Apollo. It lay in the territory of Phocis on the steep lower slope of Mount Parnassus (Parnassus, Mount), about 6 miles (10 km) from the Gulf of Corinth. Delphi is now a major archaeological site with well-preserved ruins. It was designated a UNESCO World Heritage site in 1987.

Excavations reveal that Delphi was first inhabited in late Mycenaean times (as early as the 15th century BC). Priests from Knossos brought the cult of Apollo to the site in the 8th century BC. Some 200 years later, during the First Sacred War (c. 590 BC, the Amphictyonic League (to which Delphi pertained) destroyed the nearby town of Krisa, whose taxation of visitors to the oracle had prompted the war, and free access to Delphi was opened. The League subsequently reorganized the panhellenic Pythian Games, which were held in Delphi every four years beginning in 582 BC. By then, the prestige of the Delphic oracle was at its height. It was consulted not only on private matters but also on affairs of state, and its utterances often swayed public policy. It was also consulted whenever a colony was to be sent out from Greece proper, so that its fame spread to the limits of the Greek-speaking world. Such influence led to controversy, and several more sacred wars were waged over the oracle, with control of the site shifting between rival city-states.

The site of Delphi was later occupied by the village of Kastrí, until 1890, when the village was moved and renamed Delphi. Excavations, begun in 1892, revealed the plan of the ancient site, and the remains of its buildings can be further identified in the 2nd-century-AD writings of the geographer Pausanias. The temple sanctuary was a large, roughly rectangular area enclosed by a wall. A sacred way lined with monuments and treasuries wound up through the sanctuary to the temple of Apollo itself, which housed the Delphic oracle in a chamber at the rear. The monuments along the way were offerings to Apollo erected by states or individuals in thanks for favours bestowed by the god. The existing temple site includes only the foundation, some steps, and a few columns from a structure built in the 4th century BC. Two earlier temples of Apollo at Delphi are also known from their actual remains. Some archaic capitals and wall blocks are preserved from the first temple, which was burned in 548. The second temple, built at the end of the 6th century BC, was destroyed by an earthquake; many of its wall blocks and some pediment sculptures are extant. Of the site's once-numerous treasuries, the Athens treasury has been rebuilt with the original blocks; it displays a famous wall covered with inscriptions, including musically annotated hymns to Apollo.