http://www.bbc.co.uk/science/horizon/1999/...es_script.shtml

The next one is predicted to erupt in Yellowstone park in the US. It's one of those doom day scenarios, like an asteroid hitting the Earth. But the scary thing is that "it's already supposed to have happened", which means the calculations of the scientists are slightly off, meaning that this could actually happen tomorrow. (and the US will be destroyed, along with the rest of the world... a prospect for world revolution?)