Journeys End At World's End Or Worlds' End

Another parallel between Poul Anderson and Neil Gaiman is these two titles:

"Journeys End" by Poul Anderson; (Scroll down)
Worlds' End by Neil Gaiman.

Anderson's "End" is a verb whereas Gaiman's is a noun. "Journeys" lacks an expected apostrophe whereas Worlds' has an unusually placed apostrophe.

The more familiar phrase, "world's end," is also relevant to Anderson:

 With a host of furious fancies
Whereof I am commander,
With a burning spear and a horse of air,
To the wilderness I wander.
By a knight of ghosts and shadows
I summoned am to tourney
Ten leagues beyond the wide world's end:
Methinks it is no journey.
-copied from here.