Mind Control: From the Cold War to the TV set, experts question whether the government is actively controlling what you think, how you act and what you believe. (S1, ep 3)

Doomsday: On 8 April 2011, the FBI declassified decades of top secret government documents for the first time. Here, experts examine the possibility of the end of the world. (S1, ep 1)

Convicted in 1979 for a series of contract killings, John Childs is still known as one of the UK's most prolific hitmen. This is a chilling insight into his mind.

Documentary exploring the brutality, extravagance and madness of Caligula, who ruled the Roman empire for 1,400 days before his assassination.

Dog Duty: A 1950s Space Commander ride takes Jimmie on a nostalgic trip back to his childhood. The pawn shop boss also sets his tardy staff a challenge. (S3, ep 24)

Where's The Fire?: Jimmie eyes up some fancy furniture at Alexandria's famous Bentley Hotel. The store also checks out a beautifully-restored 1929 Ford fire engine. (S3, ep 23)

Oh Say Can You Pawn?: The staff hit the road. Their travels lead them to a restored 1927 Chevy Roadster and a note signed by US National anthem writer Francis Scott Key. (S2, ep 23)

King And His Crown: The chance to buy one of Elvis' teeth leaves Jimmie and the team all shook up. Later, Johnnie comes across an intriguing vintage Batman puppet. (S3, ep 21)

Jimmie's Increasingly Bad Day: It's father versus daughter as Tammie bets Jimmie she can turn a profit on a bar-on-wheels. Plus, staff check out a 1930s horseracing game. (S4, ep 20)

4-Wheelin' Deals: The shop enters tough negotiations over a series of letters signed by Richard Nixon. Plus, Tammie and Johnnie check out a customised ATV. (S2, ep 20)