User blog comment:Zombiehunter115/What is the next "Zombies Mode" gonna be?/@comment-5670680-20140528214632/@comment-6932601-20140530103335

If you read that I forgot what it's called but it has a long post about the history behind the WaW zombies idea, they only made Zombies because they thought World At War wasn't incomplete and needed something. It changed from bunkers shooting endless enemy waves to Zombies.