The idea of the end of the world happening on December 21, 2012, stems from the ancient Mayan Calendar. The 5,125-year-long cycle calendar abruptly ends on that date, leading many to believe that it portends the end of time. Other believe that it will be the date of a shift in the spirituality of humanity marking the beginning of a new era for humanity.
There is much speculation as to what will happen on or leading up to this date. Some believe that the world will be destroyed. Others site major disasters, such as earth quakes, tsunamis, some even going as far as to believe that there will be a pole flip leading to untold problems across the planet. Some Christians believe this is the date of the return of Christ.
Conversely the scientists, scholars and astronomers think the divination of the end of times on this particular date is being overblown. The fear is being instigated by lack of knowledge, fear mongering and attachment to myths. Mayans themselves are not putting much stock into the end of times theory. They believe the end date misinterprets the Mayan history. There is no mention of a major calamity in any of the remaining Mayan literature.
The Mayan calendar was used in Central America before the arrival of the Europeans. The Mayan period was from 250 to 900 CE, during which time they developed their own writing system. This has been largely deciphered. The calendar is known as Mesoamerican Long Count Calendar, which was most likely developed my the Olmec. This format of calendar sets its beginning date at a point in the past marking the end of a pervious time period, or previous world and the beginning of a new one. The start date for this calendar has been deciphered as August 11th or 13th, as per our Gregorian calendar.
Some who decipher this end date of the calendar believe it marks the end of a Great period. To some this means the end of times for us all. There is no significance to this date found in any of the remaining Mayan inscriptions and writings. Most pieces which have survived are historical accounts, and simply do not make any prophecies about the future.
The frenzy around this date has been built up by new age authors in the 1980's and by science fiction writers. Mainstream media such as films and television shows have focused on the possibility of it portending the end of times, but the actual factual basis does not seem to be in place.
Is it the End of times? We may just have to wait and see.