Sweden's largest internet service provider is located in a place you might not expect—below 100 feet of bedrock in a former nuclear bunker. Housed in Stockholm, the Pionen Data Center contains some of the most sensitive information in the world, which at one point even included Wikileaks servers. Inside, engines intended for German submarines are now used as backup generators. But it's the architecture and design that really catch the eye. With a nod to 1970s science fiction films, the building features lush greenery adorning the walls of its cavernous digital confines. But you won't find any James Bond villains here, just the 15-person technical staff that run the servers.