Todd Sampson had climbed Mt Everest, unguided, before he ever turned a camera on himself. Since then, the award winning documentarian has embedded with Iraqi snipers, trained with the French Foreign Legion, fought in an MMA cage, and walked a high wire between two Sydney skyscrapers, all in the name of understanding what makes people tick.

Best known as the breakout star of Gruen and the mind behind Redesign My Brain, Body Hack and Mirror Mirror, Todd's latest series WHY? sees him step into the lives of Doomsday Preppers, BASE jumpers and Alien Church worshippers without judgement, just curiosity.

In this episode, Todd sits down to talk risk, fear, the plasticity of the brain, and what a career spent asking "why" has taught him about the rest of us.