One man's solo trek to the South Pole

Henry Worsley's lifetime fascination with Antarctic explorers such as Ernest Shackleton, Roald Amundsen and Robert Scott led him to retrace their expeditions in one of the most inhospitable places on Earth. In 2015 Worsley set off yet again to emulate his hero, Shackleton, by embarking on the first solo crossing of the continent. Anthony Mason talks with David Gran, author of the new book "The White Darkness," and with Worsley's wife, Joanna, about her husband's fateful trip.