10 Mind-Blowing Facts You Didn't Know About Justice League Unlimited
5. There Was A Cancelled Film
While Justice League: Crisis on Two Earths hit shelves in February of 2010, it carried with it a dark secret: it was based on the script for a previous, cancelled film.
Justice League: World's Collide was intended to be made concurrently with the first season of Justice League Unlimited, and was intended to try and fill in the gaps of what happened between season two of the Justice League cartoon, and the start of Unlimited itself.
While Bruce Timm - the architect of the DC Animated Universe - stated that World's Collide would be released to the public in no time at all, it ended up being canned. This was likely due to concerns around how to best join the Justice League cartoon with the later Unlimited universe, as Crisis on Two Earths would use much of the same script, but with all the references to the DCAU removed.