Growing up in the streets of Dundee, actor Brian Cox was surrounded by tobacco. His entire family either smoked it or chewed it and yet Brian reveals, he never took up the habit. To find out why not, Brian travels to Virginia in the US to discover how the habit of smoking kick-started the British Empire and created a global market of addicts.
The body's superhuman abilities are most starkly revealed in the area of trauma - one of the world's biggest killers. Medical teams have traditionally tried to reverse the changes which occur when the body goes into trauma, but doctors are now beginning to realise that the changes which occur in the body after an injury such as the loss of blood and severe drops in temperature serve an important purpose in the recovery process.
This time, we meet a girl with two hearts, a man who can sing two notes at once, a woman who can bend in amazing ways, a girl who is allergic to everything and a man who can run 350 miles without stopping. These remarkable cases reveal the secret inner workings of our bodies - the ultimate piece of natural engineering.
Following reports that taking extra vitamins is pointless and possibly even dangerous, Gloria discovers whether the vitamins she takes each day are really necessary or if she can get all the nutrients she needs from her food? Chris tests out a new meal plan to see what difference changing what you eat makes to how you power through the day, and even how you sleep.