What is the antonym for doomsday?

The Apocalypse (revelation) is the last book in The Bible, and therefore its antonym is Genesis, which is the first book. The Word apocalypse means "un-hidden, hence revealed," for which the antonym is mystery, which means " kept secret, not spoken." It depends on which type of apocalypse you are talking about, but if it is the one meaning "catastrophe," then some antonyms for it would be "benefit, blessing, favor, miracle, wonder, success."