Massive engineering mistakes can strike anytime, anywhere. In Montreal, a vital highway bridge collapses without warning. On Apollo 13, what really caused the explosion that made this the most dramatic space mission ever? A cutting-edge skyscraper threatens to rain down shrapnel on the city of Manchester, UK and in France, a town that's literally at breaking point.Massive engineering mistakes can strike anytime, anywhere. In Montreal, a vital highway bridge collapses without warning. On Apollo 13, what really caused the explosion that made this the most dramatic space mission ever? A cutting-edge skyscraper threatens to rain down shrapnel on the city of Manchester, UK and in France, a town that's literally at breaking point.