The oracle of Delphi in Greece was the telephone psychic of ancient times: People came from all over Europe to call on the Pythia at Mount Parnassus to have their questions about the future answered. Her answers could determine when farmers planted their fields or when an empire declared war.

The Pythia, a role filled by different women from about 1400 B.C. to A.D. 381, was the medium through which the god Apollo spoke.

According to legend, Plutarch, a priest at the Temple of Apollo, attributed Pythia's prophetic powers to vapors. Other accounts suggested the vapors may have come from a chasm in the ground.

This traditional explanation, however, has failed to satisfy scientists. In 1927, French geologists surveyed the oracle's shrine and