'How I prepared to go to the highest and lowest points on earth'

Explorer Vanessa O’Brien is the first woman in the world to reach Earth’s highest and lowest points. In 2012, Vanessa scaled Mount Everest, and this year she spent longer than any other woman at Challenger Deep – the deepest known point in the Earth’s seabed. Vanessa tells Jenni Murray what preparation she had to do and what it was like when she got to both places.

Photo by Atte Miettinen.