In 2005 Petty Officer First Class David Goggins’ life took a tragic turn. Several of his fellow U.S. Navy SEAL(s) were killed in a helicopter crash during a mission in Afghanistan. To honor them, Goggins vowed to raise money for the Special Operations Warrior Foundation, which gives college scholarships and grants to the children of fallen special operations soldiers. Goggins rationalized that to raise money, he would have to do something extreme, something phenomenal— something incredibly painful. He decided to race ultramarathons when he Googled the 10 most difficult feats in the world. First on the list was the Badwater...