Whammy

As a journalist whose career spans three decades, CNN correspondent Tom Foreman has reported from the heart of war zones, riots, and natural disasters. He has interviewed serial killers and been in the line of fire. But the most terrifying moment of his life didn't occur on the job - it occurred at home, when his 18-year-old daughter asked, "How would you feel about running a marathon with me?"

Once the reserve of only the most hardcore enthusiasts, ultra running is now a thriving global industry, with hundreds of thousands of competitors each year. But is the rise of this most brutal and challenging sport - with races that extend into hundreds of miles, often in extreme environments - an antidote to modern life, or is it a symptom of a modern illness? In The Rise of the Ultra Runners, award-winning author Adharanand Finn travels to the heart of the sport to investigate the reasons behind its rise and discover what it takes to join the ranks of these ultra athletes.