The story
From the episode “City of Walls and Secrets” of the American animated television series Avatar: The Last Airbender, aired on 22 September 2006, in which the corrupt officials of the city Ba Sing Se [Cantonese 不城碎 (bat¹ sing⁴ seoi³)] try to keep order by hypnotizing citizens to believe that "there's ^([sic]) no war in Ba Sing Se", even as the city is being besieged.
Etymology from Wiktionary, CC BY-SA 4.0.