The man who ran 50 marathons in 50 states in 50 days, among many other incredible feats, Karnazes has pushed his body and mind to inconceivable limits. In this inspiring conversation he tells Michael how he discovered his love for endurance running, what life on the run is like, and how he handles pain. They also discuss his new book, The Road To Sparta, where recounts his participation in the 153-mile race from Athens to Sparta while recounting the Ancient Greek story of the world's first marathon.