Some people have speculated that there will be a magnetic reversal of the poles, or some such thing.

There is also the theory that the Earth's crust will shift or some such thing either independently or in conjunction with the magnetic reversal.

These two world ending calamities, according to "experts", have occurred in the past and it is only a matter of time before it occurs again.

The only problem with this type of event, according to "experts", is that the only people who will survive the world ending floods, massive earthquakes, volcanoes, cohabitating cats and dogs , and other natural disasters, will be those afloat on the water, ie Noah and the Ark.

Oh my, we're doomed!