Archaeologists are good at recovering things left behind by the past, such as buildings, incense altars, tools and relief carvings. What they are not so good at recovering are the ideas, feelings and emotions of sentient ancient beings. It's one thing to examine a temple's holy of holies, it's another thing to understand what went on there and what people experienced. Sometimes, however, there's an exception to the rule. Numerous classical authors report that natural phenomena played an essential part in one of their most sacred religious rituals: the oracle at Delphi. According to the geographer Strabo (c. 64 B.C. - 25 A.D.), for example, "the seat of the oracle is a cavern hollowed down in the depths...from which arises pneuma [breath, vapor, gas] that inspires a divine state of possession". Over the past five years, a team of researchers - a geologist, an archaeologist, a chemist and a toxicologist - has put that claim to the test, making it much more likely that we will actually understand what happened at Delphi. When ancient Greeks and Romans had to make decisions, they consulted the gods by drawing lots, casting dice, interpreting dreams and analyzing such signs as sneezes, thunderbolts and flying birds. But for matters of the utmost importance, they sought to hear the words of the gods in the mouths of oracles. Paradoxically, in male dominated classical Greece the most influential voice, the Delphic oracle, belonged to a woman. The oracular temple was perched on the south slope of Mount Parnassus, surrounded by high cliffs, about 75 miles west of  Athens. Getting to Delphi required either a long trek across the mountains or a sea voyage to the north shore of the Gulf of Corinth. However difficult the journey, thousands of visitors sought guidance from the holy woman, called the *Pythia, who spoke on behalf of the gods. *Pythias were virgins who dedicated their lives to prophesying on behalf of the god Apollo. The first Pythia is said to have been the goddess Themis. According to sources, the Pythia was inspired by mysterious vapors, though these accounts have been largely ignored by modern researchers. Now, however, a team of archaeologists and geologists have proved that the Temple of Apollo sat directly above fault lines that likely released intoxicating carbon based gases into the adytum. Was this the oracle's secret?