Greek tradition counted five temples at Delphi. The first was a hut woven from laurel branches brought from the Vale of Tempe. The second was said to have been built of beeswax and feathers, a gift from Apollo to a mythical northern people called the Hyperboreans. The third was bronze, supposedly forged by Hephaestus himself. Pausanias, writing in the 2nd century AD, doubted these stories but recorded them anyway. The fourth temple was real - a stone building constructed by Trophonius and Agamedes - and it burned down in 548 BC. The fifth temple, financed by donations from across the Greek world and from as far afield as Egypt where King Amasis II contributed a thousand talents, was completed by 490 BC. An earthquake leveled it in 373 BC. They rebuilt it. The ruins visible at the site today are this last reconstruction, finished in the 4th century BC and finally closed by order of the emperor Theodosius I in 390 AD.

Greek myth held that Zeus released two eagles from the ends of the Earth, and they met at Delphi. The exact spot where they met was marked by the omphalos, the navel stone, kept inside the temple's adyton. This was the center of the universe. The temple sat on a sloped terrace partway up Mount Parnassus, with the cliffs of the Phaedriades rising directly behind it and the deep Pleistos Valley falling away in front. Polygonal masonry walls, still standing, were inscribed with hundreds of legal texts: emancipations of slaves who had dedicated themselves to Apollo as the legal mechanism of their freedom, eulogies for benefactors, decrees of the Amphictyonic League. To stand among those inscriptions is to read three centuries of Greek civic life carved into limestone.

The oracle was always a woman. In the earliest period she was selected from among the Delphic women. After one of the Pythias was sexually assaulted by a man named Echecrates of Thessaly who had come for a prophecy, the priesthood changed the rules. Future Pythias had to be at least fifty years old, though they continued to dress as young women. The work was not safe and not glamorous. Inquirers brought sacrificial animals - goats, sheep, bulls - and burned them on the altar outside. If the omens were favorable, the Pythia descended into the chamber beneath the temple, sat on a tripod over the fissure, was cleansed with water from the Castalian spring, and spoke. A priest above interpreted what came up through the floor. Modern geological surveys have identified active fault zones beneath the temple capable of releasing hydrocarbon gases - ethylene among them - that could indeed produce trance states. The ancient stories about a woman in a chamber breathing vapors and uttering broken Greek may have been describing something a geologist would recognize.

Cities competed to honor Apollo at Delphi. Treasuries lined the Sacred Way - small marble buildings full of votive offerings from Athens, Sparta, Siphnos, Thebes, and dozens more. Persian shields from the Battle of Marathon hung on the temple's exterior. Gallic shields from a failed invasion in 279 BC hung beside them. Herodotus joked that the Persian king Xerxes I would have been more familiar with Delphic wealth than with his own treasury. Such concentrated riches inevitably drew armies. The Sacred Wars - five separate conflicts spanning three centuries - were fought over control of this site. During the Third Sacred War in 357 BC, the Phocians seized Delphi, looted the temple, and used an estimated 10,000 talents of treasure to fund a mercenary army. Imagine the contortion: an army marching to war on the melted-down offerings of the people who had come to Apollo for guidance about whether to make war.

The oracle's last recorded prophecy, delivered to an emissary of the emperor Julian in 362 AD, said the temple was silent and the spring had stopped speaking. Theodosius closed it officially in 390 AD. For fifteen hundred years the village of Kastri sprawled across the ruins. In 1891 the French government negotiated the village's relocation, and from 1892 to 1894 archaeologist Theophile Homolle led the systematic excavation of the entire site. The Charioteer of Delphi - a near-life-size bronze statue, miraculously preserved - was lifted from the rubble. So were the Dancers of Delphi, a sphinx, and the Antinous statue Hadrian had dedicated when his lover died. Walking among the columns of the temple today, with Mount Parnassus rising behind you, it is hard not to feel some of what those ancient pilgrims felt - the silence, the height, the weight of the rock. The voice that once spoke from beneath the floor has been silent for sixteen centuries. The site still asks the question it inscribed at its door: Know thyself.