FIRST OF ALL, I am unaware whether necroposting is acceptable in the Serious Discussion.
Second, I do believe that it was the Mayans' religion of sorts that made them end it at that date. If I recall correctly from a documentary, the Mayans believed that the Gods made a type of human creature and it did not meet their expectations. So they eradicated them after 5126 or so years. 5126 years after that, they did the same to the new race. 5126 years after that, they destroyed the third race and we came around.
Apparently December 21, 2012 is supposed to be the end of the 5126 or w/e years.
I don't believe this, but I decided to clear up the issue of WHY it ended on that date, even if it was being debated over a year ago...
I just figured with the releases of various 2012 theory documentaries and the Movie 2012 that people would have new opinions and such :( (I know of 3 documentaries at least, though I've only watched 2)
The reason people thought the world was ending in 2021 was because the mayan calender ended in 2012,recently that theory was blown out of the water,as they found missing pieces of the calendar that prove it doesn't end in 2012.