Black Ops: The truth behind America's most dangerous and clandestine operations. What makes a top-secret assignment a black op? And how do soldiers prepare for them? (S1, ep 9)
Secret Underground: Uncover the cities and government fortresses covertly constructed beneath American soil, including an advanced network of drug smuggling tunnels. (S3, ep 8)
The Drug Wars: Documentary uncovering the conspiracies behind America's 40-year drugs campaign. Could laundered drugs money be keeping the fragile global economy afloat? (S2, ep 8)
West Point: Head inside the academy at West Point and discover the mysteries and traditions surrounding the secretive New York launch pad for presidents and army elites. (S2, ep 8)
Billionaire Agenda: Investigation into the growing power and wealth of the US's super rich, including how billionaires' 'dark money' is being used to influence politics. (S3, ep 7)
Presidential Cover-Ups: Go behind the headlines and uncover the real stories behind the greatest White House scandals of recent times. (S2, ep 7)
The FBI: An inside look at America's most powerful police force. Formed of Special Agents, its mission is public knowledge but its tactics are top-secret. (S1, ep 7)
...of Secrets. Secret Prisons: Documentary exploring the biggest scandals and conspiracies to rock the US prison system, including Pennsylvania's 2008 'kids for cash' scandal. (S3, ep 6)
Deadly Cults: A look at the strange allure of cults, their leaders and how they control their members. A Jonestown survivor remembers the last days of the Peoples Temple. (S2, ep 6)
Presidential Transports: A look behind the bulletproof glass and armoured plating of the president's fleet of vehicles, from Air Force One to the limo known as The Beast. (S1, ep 6)