Mesoamerican calendars was of ritual significance to a number of Mesoamerican cultures. A third major calendar form known as the Long Count is found in the inscriptions of several Mesoamerican cultures, most famously those of the Maya civilization who developed it to its fullest extent during the Classic period (ca. 200–900 CE). The Long Count provided the ability to uniquely identify days over a much longer period of time, by combining a sequence of day-counts or cycles of increasing length, calculated or set from a particular date in the mythical past. Most commonly, five such higher-order cycles in a modified vigesimal (base-20)
Maya calendar Long Count was particularly well suited to use on monuments. The monumental inscriptions would not only include the 5 digits of the Long Count, but would also include the two tzolk'in characters followed by the two haab' characters. Misinterpretation of the Mesoamerican Long Count calendar was the basis for a popular belief that a cataclysm would take place on December 21, 2012. December 21, 2012 was simply the day that the calendar went to the next b'ak'tun, at Long Count 13.0.0.0.0. The date on which the calendar will go to the next piktun (a complete series of 20 b'ak'tuns), at