Okay,here's the long and short of it; the Mayans had two calendars which were also adopted by other pre-Columbian cultures such as the Aztecs. They had a calendar that cycled every 52 years. They also had one that cycled every 5,126 years and started in 3114 B. C. when you compare ours with that one it comes out to 12/21/12. BUT there have been many adjustments to our calendar over the centuries such as leap days and days dropped out of months etc. that the dates might not line up. Some people say that the Milky Way will be lined up a certain way and there will be solar flares and gravitational shifts etc. Those people are smarter than me or maybe they have more time to waste on pointless speculation. My advise: anytime someone gives an exact date for the end of the world bet everything you can on that NOT being the date. If you lose,hey it's the end of the world who's going to collect? If you win it's payday!