For an exciting story, nothing beats a real-life action hero. Mongolia is pretty big, but it wasn't big enough for chieftain Kubla Khan, so in about 1260 he set off to conquer China, making himself ruler over much of Asia by the time he died. The secret of his success was mostly being clever and ruthless, but he also tried to rule fairly, encouraged learning and science, tolerated other religions, and didn’t cut people’s heads off if they disagreed with him (although he sometimes made them shave). Italian traveler Marco Polo brought back such fantastic tales of the marvels of the Great Khan’s empire that they later inspired Christopher Columbus to set off westward to look for it, though America unfortunately got in the way.