The oracle at Delphi was consulted before any important step was taken in affairs of state.
All of the city-states in Greece contributed funds
to the Temple of Apollo.
A massive temple stood on one of the very few spots in the sanctuary that was level. Above the temple door were carved such admonitions such as "Know Thyself".
This was where all those wishing to consult the Oracle would come. The Oracle of Delphi was a spiritual experience, in which advice and questions were asked to the spirit of Apollo.
The reply from Apollo would be channeled through priestesses, known as Pythia, who would be seated on a tripod over a mysterious chasm that expelled mystic vapors, said to enhance the channeling of Apollo.
Let the Oracle Speak!
Interactive Voice Response Systems (IVR)