Doctor of extreme medicine, Kevin Fong, sets out to discover how unsuited human biology is to living on much of the planet... and how we have developed the technology to let us survive there.
In the first programme, To Bodly Go Down, it's about how to survive underwater as Kevin escapes from a sinking helicopter, walks through a tank of sharks in an antique diving suit and intentionally gives himself nitrogen narcosis.
In the second episode (To Boldly Go Up) Kevin is going up to find out how the body responds to altitude. The short answer to that question is: badly. Kevin climbs one of the tallest mountains in the Alps, and subjecting himself to a sudden depressurisation to 25,000 feet. But although we struggle to deal with altitude, the defining story of 20th-century technology was our quest to leave the surface of the earth behind and travel up through the atmosphere and into space.
The natural home of our species is at sea level. Even today more than three-quarters of the world's population live at altitudes below 500m. And there is a very good reason for that - the higher we go, the less oxygen there is in the air and the harder we find it to survive.