Mysteries and conspiracies in the U.S. are examined in this series, which begins with former CIA officer Mike Baker and actor Richard Belzer investigating the assassination of John F. Kennedy. Other segments look into the disposal of radioactive waste; and explore a quiet zone.

An investigation into the 1971 disappearance of airplane hijacker D.B. Cooper, who parachuted from Northwest Airlines flight 727 with $200,000 and was never seen or heard from again. Also: the case of a toxic sinkhole that's threatening to swallow an entire Louisiana town; and criticism over a U.S. government roundup of wild horses in the West.

Follow our investigators as they gain access to restricted locations, go behind the barbed wire fences and ignore "Do Not Enter" signs to uncover the forbidden information Americans want to know. Could Denver International Airport conceal a massive secret underground doomsday bunker? What is really happening at New Mexico's White Sands Missile Range? Finally, will the NSA's new, billion-dollar data center collect electronic correspondence from everyday American citizens?