Run in the dark

Mark Pollock: explorer, 38

In 1998, I went blind after suffering detached retinas. I was 22. In the years that followed, I won medals for Northern Ireland in the Commonwealth rowing championships. I ran six marathons in seven days across the Gobi Desert, completed the North Pole Arctic Marathon and the Tenzing Hillary Everest Marathon, did the Round Ireland Yacht Race, and became the first blind person to race to the South Pole ...