I don't think this is really a valid question because a portion of the bible did indeed happen. Most of it are fantasy, sure, but to classify it as a book of fiction is a bit much.

The bible, as we know it today, is actually not what Jesus and his followers wanted to get out. It has been through so many revisions, versions, cencorships. It's been twisted by politicians of old to get across some agenda or some other belief. It's a bit stupid for anybody today to actually believe what the bible has to say.

I'm not relegious, for the record.