The year 2012 is not the end of the world; it's simply that the Earth has entered a Photon Belt. However, at the moment of complete entry, we will endure three days in a 0-degree space. Undoubtedly, many people will die, magnetic poles will reverse, and our current 3-dimensional space will regress to a 0-dimensional space, which seems like destruction. However, a brand new world will follow, and many people will survive through those three days. During these three days, the solar system undergoes significant chemical changes within the Photon Belt, leading to the recombination of atoms in the human body. This marks the arrival of a 4-dimensional space and the beginning of the Fifth Era.
In my personal understanding, the Mayans were not predicting the end of the world. They clearly wrote about the darkness arriving on December 21, 2012, with the dawn of December 22 not coming. It seems the Mayans lived in the same 3-dimensional space as us, so naturally they could not foresee the events of the 4-dimensional space. Moreover, if there's no daylight on December 22, after three days—around Christmas—daylight will return!