End of the world?

We don't want to alarm anyone - but according to some - the world will end tomorrow.

End of the world?

Tourists are seen at the Mayan ruins of Tikal, 500 km north of Guatemala City. Photo: AAP

That is not the end of the world as we know it - but as the ancient Mayans did. But some are still getting ready - just in case.

In the U.S, companies which build elaborate bunkers have reported a rush on sales. So have army supply stores.

NASA says there's nothing to worry about and even some extreme survivalists are skeptical.

And it's not the first time the world was supposed to end..

Remember Nostrodamus? Y2K and the Millennium Bug? American radio host Harold Camping?

All prophets of doom; all failed.

So far, anyway.

So what is all the fuss about?

According to the Mayan calendar, the world is predicted to end on 21 December, where a 5,125 year cycle will stop, inevitably leading to an apocalypse.

The Mayan calendar finishes one of its cycles, the Long Count, on this particular day which has led to countless theories about the world coming to a close.

Some believe a rogue planet called 'Nibiru' will emerge from its hiding place behind the sun and smash into the Earth.

Doomsday predictions throughout time

Others say a super black hole at the centre of the universe will suck in our planet and smash it to pieces. A major natural disaster has also been predicted.

Thousands of people have been preparing for this 'doomsday' by building underground panic rooms and filling secure bunkers with food and supplies. Whilst others are preparing mass party celebrations to mark the end of the world as we know it.