Wildlife presenter Sir David Attenborough has been left "astonished" by his hike to the North Pole which saw him fulfil a long-held ambition.
The 83-year-old broadcaster travelled to the "last great wilderness" to film for the natural history series, the Frozen Planet.
The BBC1 programme is due to air late next year and the seven episodes will treat viewers to a polar expedition "before the regions change forever".
The last episode, Meltdown, will be written and presented by Sir David who will examine the impact of climate change.
He will look at what the future might hold for the animals and people who live at the Poles and what it might mean for everyone else.
Speaking from the Svalbard archipelago, 700 miles from the North Pole, he said: "The Poles - North and South - look superficially very similar but when you visit them within a few weeks of one another, as I have just done, you realise how profoundly different they are and how what is happening to them is going to affect the entire planet.
"Having seen what I've just seen - from penguins to polar bears, from the frozen ocean to snow-covered volcanoes - I can't imagine why I've left visiting these marvellous, astonishing and beautiful places until so late in my life."