Robert Swan is considered one of the greatest explorers of all time. At the age of 60, he took the longest documented hike in human history, walking 900 miles in 70 days to reach the South Pole. He achieved this incredible expedition alongside his son and they became the first ever team to make the trip surviving entirely on renewable energy. That followed his feat 30 years earlier of hiking to the North Pole. His journeys have turned him into a passionate eco-warrior and he’s on a mission to save the environment. He explains how.