In the aftermath of Judgment Day, we fled to the Exclusion Zone and sought refuge underground. This is what is left of our fallen civilization.

“This whole movie was actually just cameras following around Jack black as he illegally entered a school”
https://www.youtube.com/watch?v=yMvpJDbWX_c&lc=UgySaLmS_odyMECOH6h4AaABAg