Watch at FMovies. As only National Geographic can, The Great Quake tells the terrifying and inspiring tale of a pitched battle between man and nature told by the stories of people who lived through it. On April 18, 1906 the greatest natural disaster in American history strikes without warning. Concrete buildings explode into clouds of dust and rubble and fires break out by the thousands. For the next three days, San Francisco's corrupt and charismatic Mayor takes the helm of this city under siege, making decisions that are swift and radical. This is the terrifying and inspiring tale of a pitched battle between man and nature told by the stories of people who lived through it.