The New Madrid Fault Zone is a large area in the central United States consisting of a couple of main faults and numerous secondary faults, as well as other significant geological structures and features. It produced an historic series of severe quakes in the winter of 1811-12, and it continues active to this day. It has a danger potential possibly exceeding that of the San Andreas fault plate boundary, but few people have ever heard of it. How did it form, what areas are in danger from it, and why is it so dangerous?