Genghis searches for immortality. He can forge a nation, wage war against mighty foes, and crush whole cities beneath his leather boots. But even Genghis Khan is powerless to stem the decay of his own body. About 55 years old, he sends for Changchun, a Taoist sage believed to know the secret of long life. The old monk can only disappoint the eager conqueror: “If neither heaven nor earth can achieve permanence, how much less can man do so?” Still, Genghis hails the sage as a holy man, and the two become friends and correspondents.   © 1997 National Geographic Society. All rights reserved.