The currents of History run deep and often unseen beneath the everyday ripple of events. But now and again the current rises to the surface, and the events of a single day shed an exceptional light on the meaning of the past. Such events are the subject of "Days that Changed the World". Some of the 50 days described here mark the end of an era; others the start of something new. Many are the dates of bloody battles or murders; others of momentous decisions or breathtaking discoveries. All are remembered as powerful symbols of their time.