He did it again. Dean Karnazes broke 4 hours for the second day in a row--with a raging head cold, in high altitude, following 8 straight days of 26.2 mile runs. Quite simply: amazing. He is starting to make his Endurance 50 quest to run 50 marathons in 50 days in all 50 states look almost easy. Next stop: Deadwood, South Dakota.