Return to Life (E04)

Legendary climber Conrad Anker and his mentee David Lama want to be the first to summit Lunag Ri, the tallest unclimbed peak in the Himalayas. As they struggle on the side of the mountain, at an altitude of 20,000 feet and glacial temperatures, Conrad grasps for air and suddenly feels a pain in his chest. He realizes he is having a heart attack in one of the most inhospitable places on Earth. (National Geographic)