Before Carnival Cruise Line had even begun thinking about its Vista, there was Pinnacle, and it was to be massive, featuring a monorail running around ship's outside edge (just like the SkyRide does the newer liners) and a lazy river on expanded promenade deck. Watch to see what went wrong.
Pinnacle never came to pass (due in part to an incredible price tag), a lot of elements of her innovative design have been adapted for other ships and competing cruise lines.