Imagine Dragons - Fallen Lyrics Meaning

It is talking about the fall of the oracle of Delphi for after the ethylene gas stoped coming from the crack in the earth the oracle of Delphi stopped with it and a roman wanted to start the prophecies of the oracle again and start the oracle of Delphi again but the last photogravure said that Apollo had left them and the time has past to resurrect the Greek beliefs which is mentioned at the end of the song. Imagine dragons have a few songs that have to do with the Greek gods. Like Selene wich is a Greek goddess.