Each hour of this series will take viewers on a captivating, revealing and at times shocking tour of America's past, revisiting its most crucial events by reexamining what has been left behind. The series casts its net wide, exploring the corners and backrooms of institutions dedicated to a variety of popular and entertaining subjects — invisible spies, cold-blooded assassins, dinosaurs, the paranormal, the Old West, the Cold War and more. We'll tackle some of history's most enduring mysteries — both familiar tales and little-known episodes that have never been told before on television.