Imaginary comes to mind.
Naah. The story is too cross-culturally widespread and significant to be pure fiction. My personal view (and I am not a theologian, mind you) is that the ancient world was far, far stranger than many of us suspect in terms of its physical structure, and that mankind's earliest texts are obscure because they represent the efforts of unsophisticated herdsmen to understand and express events far beyond their own experience. I think most of the events in Genesis really happened, but the Bronze Age tribesmen who witnessed them (or who were shown them by Divine revelation or whatever) were unable to describe what they were seeing in technically sophisticated terms. With nothing but Bronze Age cultural referents, the writers of the Genesis texts had no choice but to fall back upon imagery that their readers could comprehend. Thus the creation stories of apples, serpents, and sunless days -- attempts by the authors to describe nearly incomprehensible cosmic events in terms their fellows could understand. Ditto the Ark (which means something more like "container" than "ship" in the original); who knows what it really was? For all we know it was a framework of negative matter with an entire "pocket universe" inside, a universe capable of supporting the ecosystem that Noah and his family were instructed to save. Jewish legends are instructive in this regard; many contain extra data that can be interpreted to support the idea that there were some mighty odd things going on back in the really old days -- things like physical laws being different, for example.
As a Catholic, I believe the Bible is true and inspired by God, and is in no way a work of fiction. In my opinion, however, the great truths of the Pentateuch are spiritual, rather than literally historical. Adam and Eve really existed, but they and the Garden they inhabited were part and parcel of a non-entropic and metaphysical universe quite different than the fallen universe of physics and entropy we now inhabit. Adam was not "a" man; he was Man, the perfect Image of God made flesh, and whatever that entailed I don't think we are well served by continuing to imagine him as a character in a child's picture book.
God chose to reveal the story of creation to unsophisticated itenerant tribesmen of six millenia ago. One can hardly blame them for relating whatt they saw in terms an unsophisticated itenerant tribesman could understand -- a folktale. If God revealed the creation of the universe to a modern day man, I suspect that Genesis would read more like a science-fiction novel -- our modern-day folktale. Instead of trying to puzzle out the tale of our creation in medieval terms, I think we might be better served by re-examining the "mythology" of the Genesis story in the light of our culture's own myths and legends -- i.e. science-fiction. A re-examination of the Bible from an SF perspective could lead to insights we have missed.