we have]iom just landed in wic kansas. in a place were they take doomsday very seriously.ompletely off the grid. in the middle of nowhere, yup, we have arrived. how are you? i hope we're in the right place. we're with "nightline"? inside, a warm welcome. raven's ridge of kansas, site 11. a former ballistic missile silo. a structure the u.s. government built with doomsday in mind and one which was repurposed with a different doomsday in mind. it's a luxury apartment complex. it goes 15 stories down. >> let's get you settled in your room. >> reporter: we're here for a sleepover. your average bed and breakfast is not this heavily fortified. >> all of the walls are nine feet thick. >> reporter: this is a luxury condo tower. going for $1.5 million a pop. >> let me show you the pool. >> reporter: it's 85 degrees and so humid it fogs up our camera lens. there's even waterfall. they're the high end of a booming business. more than 3 million americans are thought to be committed preppers. most having more modest scena o scenari scenarios. it's a $500 million a year thing. survivali