Ed Pedin purchased this defunct missile silo in 1983, but it took about a decade of renovations to make it a livable home. Pumping out more than 8 feet of rainwater that accumulated while the site was inactive was one of many makeover challenges. Not many homeowners can say their house once stored a four-megaton nuclear warhead. What was once the launch control station, Pedin says, is now a cozy living space. Transforming a nuclear launch pad into a residential castle has lots of benefits, such as an 11,000-square-foot garage and a 1,700-foot-long airstrip, which came in particularly useful when Pedin was experimenting with do-it-yourself ultralight aircraft. Since the completion of Subterra Castle, Pedin has become a mogul of sorts, creating 20th Century Castles LLC, a real-estate firm specializing in converting missile silos.