Kovner's $27.5 million fifth avenue fortress (including $10 million in renovations

Caxton Associates founder Bruce Kovner bought this beautiful Georgian mansion in 1999 and converted it to a science fiction fortress.

From Cityfile: The home features a two-story master bedroom, more than a dozen baths, a book vault, and a media room that is entirely soundproof. The secretive billionaire is also believed to have installed a lead-lined "safe room" on the fourth floor of his townhouse that's capable of protecting Kovner in the event of a dirty bomb or chemical weapons attack.