Audio slideshow: Human Planet

From the icy Arctic to Africa's dense jungles - and the mountain tops of Mongolia to the deep waters of the Pacific - the BBC series Human Planet has explored mankind's incredible relationship with nature.

Accompanying the film crews was photographer Timothy Allen. His stunning still images captured unique glimpses of people living in the world's most extreme environments. Take a look at some of them, and listen to him explain how he snapped the most arresting shots.