Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online.Risks to civilization, humans and planet Earth - Plate tectonics, Flash flood, Assault, Gamma-ray burst, Ice age, Pandemic, Megatsunami, Pole shift hypothesis, Supervolcano, 2012 Doomsday prediction, Existential risk, Malthusian catastrophe, Near-Earth supernova, Societal collapse, Extinction event