Sparks of Invention

A look at four inventions that shocked the world. Ouija, a game that claims to talk to the dead, Dynamite, an explosive invented to save lives, the electric chair and the rollercoaster.

Meet a young farm worker whose electric idea keeps us entertained, an astronomer who wants to see the birth of stars and an attorney whose copier terrifies governments.

A look at expensive innovations within the world of crime, including an alarm that keeps the crooks at bay, a device that revolutionises retail and a gun loved by bad guys.