In the history of the world there have been lots of onces and lots of times, and every time has had a once upon it. Most people will tell you that the once upon a time happened in a land far, far away, but it really depends on where you are. The once upon a time may have been just outside your back door. It may have been beneath your very feet. It might not have been in a land at all but deep in the sea's belly or bobbing around on its back.
N. D. Wilson (2008). “Leepike Ridge”, p.1, Random House Books for Young Readers