What will happen on December 21, 2012?

All major catastrophic events that you have ever known will come in a single strike and washout humanity. this was said by the Mayans on their prophecy, which is the end of the world, a crust displacement will occur causing both poles to shift and because of this earth will go back on its starting point which there will again the formation of the PANGEA thing. and everything will go back to original, its like a cycle, actually the earth have been destroyed 3x already and it is the 4th, on december 21, 2012.