During the 1990s, Steven Spielberg's animation studio was working on an adaptation of Andrew Lloyd Webber's mystical musical Cats. The movie fizzled out when the studio closed, which is a shame, because judging from this artwork, it would have looked spectacular.
Amblimation, which produced An American Tail: Fievel Goes West, We're Back! A Dinosaur's Story, and Balto (as well as the Back to the Future TV series), was developing an animated Cats movie directed by Simon Wells and Phil Nibbelink. When Amblimation shut its doors in 1997, the project was abandoned.
Luc Desmarchelier, who worked in visual development on the film, has posted some of his Cats artwork, filled with grand settings:
But Spielberg wanted the Jellicle Ball to be set in London after the blitz, so production designer Hans Bacher worked with John Napier, the set designer for the stage show, to create images of the destroyed city the cats would sing and dance through:
Brucher has more information about his experience working on Cats—as well as his process in designing these environments—on his blog.