By the mid-2000s, Kenyan athletes had done something that seemed statistically impossible. They were winning not just the world's major marathons, but dominating them. At Boston, New York, London and Berlin, the podiums were filled with Kenyan names. Catherine Ndereba won Boston four times. Paul Tergat set the world record in Berlin. The runners came from the same hills, trained at the same altitude, and ran with an efficiency that scientists could not fully explain. Kenyans had not just won distance running. They had made it theirs.