From Mongolia to Turkey, thanks to discoveries made in four lost cities dating from the Middle Ages, historians and archaeologists reveal how Genghis Khan, creator of the Mongol Empire, and his descendants managed to maintain order and peace in the largest contiguous empire in history. Far from the clichés associated with barbarian warriors, the Mongols, a nomadic people, turned out to be fine politicians and, more surprisingly, great builders of cities in which a peaceful multicultural society lived…