The lyrics are impressionistic, aside from a clear, early reference to the victims of the eruption of Mount Vesuvius—a tragedy that may or may not keep coming up throughout the song and may or may not serve as a stand-in for the tragedy of 9/11. Who knows? The meaning of a dream is rarely overt. More likely, you’re left with just the feelings it inspired—and everyone you describe it to is going to have a different interpretation.