The intrepid Oxford don, explorer and author of "Going to Extremes" is back, and he's set himself a challenge to cope with the worst that nature can throw at him. Travelling to four of the most extreme natural environments: swamps, deserts, jungles and arctic wastelands, the question is can he pick up enough tips from the indigenous people to hack it at the very edge of human existence, or will his mid-latitude sensibilities forever let him down? This is Nick's account of how he put his body and mind to the test in a survival experiment.