That is how the world’s energy is wasted. In complete irrationality! Complete futility! For the Great Wall—and it is gigantic, a wall-fortress, stretching for thousands of kilometers through uninhabited mountains and wilderness, an object of pride and, as I have mentioned, one of the wonders of the world—is also proof of a kind of human weakness, of an aberration, of a horrifying mistake; it is evidence of a historical inability of people in this part of the planet to communicate, to confer and jointly determine how best to deploy enormous reserves of human energy and intellect.