Delphi is both an archaeological site and a modern town in Greece on the south-western spur of Mount Parnassus in the valley of Phocis. In myths dating to the classical period of Ancient Greece (510-323 BC), the site of Delphi was believed to be determined by Zeus when he sought to find the centre of his "Grandmother Earth" (Ge, Gaea, or Gaia). He sent two eagles flying from the eastern and western extremities, and the path of the eagles crossed over Delphi where the omphalos, or navel of Gaia was found.

Earlier myths include traditions that Pythia, or the Delphic oracle, already was the site of an important oracle in the pre-classical Greek world (as early as 1400 BC) and, rededicated, served as the major site during classical times for the worship of the god Apollo after he slew Python, "a dragon" who lived there and protected the navel of the Earth. "Python" (derived from the verb pythein, "to rot") is claimed by some to be the original name of the site in recognition of Python which Apollo defeated. The Homeric Hymn to Delphic Apollo recalled that the ancient name of this site had been Krisa. Others relate that it was named Pytho and that Pythia, the priestess serving as the oracle, was chosen from their ranks by a group of priestesses who officiated at the temple.

In the inner hestia ("hearth") of the Temple of Apollo, an eternal flame burned. After the battle of Plataea, the Greek cities extinguished their fires and brought new fire from the hearth of Greece, at Delphi; in the foundation stories of several Greek colonies, the founding colonists were first dedicated at Delphi.