Maya had several calendars. They have a 365-day solar calendar a long and a ritual calendar of 260 days long. Both calendars will sync every 52 years. To measure a longer time period, they develop "a long calculation" calendar, the date expressed as a series of five numbers, each less than twenty; something like the way we measure the minutes and seconds as a series of two numbers each less than sixty .
And, only in this case may seem too simple, because the reason for the second last number is always less than eighteen years. The first day of the Mayan calendar long count expressed as 0.0.0.0.0, and our calendar, this August 11 3114 BC. 144,000 every day (or about every 395 years, which they call baktun), the first number will increase, and new baktun will begin. Remember how we all should enjoy the excitement of watching the show digital millennium rolled from 12/31/1999 to 1/1/2000? Well, that's what will happen on December 21 2012 Mayan calendar. This will roll over from 12.19.19.17.19 to 13.0.0.0.0, as he had done each of the previous twelve baktuns. There is no archaeological or historical evidence that the Maya themselves are expected anything other than New Year's Eve party occurred on this date: Claims that this rollover represents the Mayan predictions end of the world seems to be the invention of modern pop culture. It is true that the Mayan calendar carved their 13 baktuns just described, but what do you expect them to do? Old calendar carve an infinite every time they want to express a date? Can be a simple explanation like they did not expect the people in the 21st century to remain obsessed with their ancient calendar.