"It is not for you to know the times or dates the Father has set by his own authority" (Acts1,7).
According to the Mayan calendar, the world is going to come to an abrupt end on 21/12/12. For some Christians, the end of the world will be known by a rupture. The "rupture" is a relatively recent teaching introduced by fundamentalists who took several unrelated Scripture texts and devised a frightening scenario. Christ, besides coming at the end of time, will come a few years earlier to snatch (to seize) all the "just" from the earth in a single instant, leaving the "unjust" behind. Satan will be unchained to roam freely about the world wreaking havoc among the unjust. After a time, the Lord will come again and conquer Satan, and the world will end.
How did such a teaching come about? By interpreting symbolic Scripture texts literally, and also piecing together unrelated texts. To cite one example: In about the year 50 A.D., some Christians in Thessalonica worried that those who had already died would miss the second coming of Christ. Paul assures them that the dead would be raised. He adds:"Then we who are alive, who are left, will be caught up together with them in the clouds to meet the Lord in the air". Paul is simply saying that at the end of time we will all go to God. Yet, this is a standard text used to prove the "rupture" of the just ahead of time. (Bishop Ken Untener, The Little Blue Book,2012).