TODAY | June 21, 2013
>> pitt's new movie " world war z " is now out in theaters.
>> it got us thinking what is with the undead's rise in popularity. here's keith miller .
>> they're coming, ready.
>> reporter: the undead have never been so alive. on screen, zombies have hit the big time .
>> oh it's a zombie.
>> the undead once confined to come disand the cut movie circuit are suddenly everywhere. there are games, apps and even websites giving tips on how to tell if your coworkers are among the living dead . exterminating them is a popular role playing game . this zombie boot camp in rural england trains people to battle the undead. so how was it? the director has more than 8,000 recruits. what motivates people to come out here and enjoy zombie boot camp ? what is that.
>> they want the challenge. it's as real as we could do it without killing anybody.
>> they look dead to me. the attraction of the zombie films is all about us, the individuals, surviving the onslot. scientists have even pondered what would happen if the undead really got hungry. a zombie outbreak is likely to lead to the collapse of civilization unless it is dealt with quickly inches life as we know it will come to an end in 90 days .
>> reporter: escaping underground to avoid the zombie apocalypse speaks to modern day fears of pandemics, disasters and the social collapse depicted in the news every day. this horror fiction challenges man's instinct to fight or flight and asks what would you do? for today, keith miller , nbc news, england.