If you’re planning a trip to Greece in the future, you’ll want to schedule a visit to the temple of Apollo at Delphi. This famous temple was the home of the Pythia, a specially chosen and trained woman who, according to legend, channeled the voice and wisdom of Apollo, the god of prophecy. Generals, politicians, and private citizens of the ancient world flocked to Delphi to question the Pythia and seek her divinely inspired advice. Ancient scientists and philosophers attributed the oracle’s power to vapors that bubbled up through a chasm and spring running through the oracle’s chamber inside the temple. Inhaling these vapors, according to the ancients, induced a trance-like state that endowed the oracles with divine prophetic power. Around 1900, excavations at Delphi revealed no chasm or escaping gasses, and so the ancient accounts were discredited.