Throughout history some of mankind's proudest moments have come at the hands of its engineers. In the ancient world the Colossus at Rhodes, the Pyramids of Egypt, and the Great Wall of China, and modern triumphs like the Hoover Dam, the Space Shuttle, and the Golden Gate Bridge, all have the power to awe us and make us feel proud to be human. But what happens when the engineers fail, when their calculations are wrong, when it all come tumbling down? Throughout history it has meant disaster. Just as in the time of Hammurabi, who passed the first laws concerning inadequate construction, buildings collapse even today -much bigger buildings than Hammurabi ever dreamed of. In the modern world the stakes are much higher - but engineers are just as human as they ever were. An engineering disaster involving a passenger jet can jeopardize hundreds of innocent people. And if a nuclear or chemical plant is involved, it can mean death for thousands. For the first time in history, engineers now have the power to wipe out entire cities, by mistake.