2012 phenomenon: Festivities are held in parts of Mesoamerica to commemorate the conclusion of b’ak’tun 13, a roughly 5,126-year-long cycle in the Mesoamerican Long Count Calendar whose passing many New Age spiritualists had earlier held to portend a variety of cataclysmic or transformative events.

The 2012 phenomenon was a range of eschatological beliefs that cataclysmic or transformative events would occur on or around 21 December 2012. This date was regarded as the end-date of a 5,126-year-long cycle in the Mesoamerican Long Count calendar, and festivities took place on 21 December 2012 to commemorate the event in the countries that were part of the Maya civilization, with main events at Chichén Itzá in Mexico and Tikal in Guatemala.

The Mesoamerican Long Count calendar is a non-repeating base-20 and base-18 calendar used by pre-Columbian Mesoamerican cultures, most notably the Maya. For this reason, it is often known as the Maya Long Count calendar. Using a modified vigesimal tally, the Long Count calendar identifies a day by counting the number of days passed since a mythical creation date that corresponds to August 11, 3114 BCE in the proleptic Gregorian calendar. The Long Count calendar was widely used on monuments.

New Age is a range of spiritual or religious practices and beliefs that rapidly grew in Western society during the early 1970s. Its highly eclectic and unsystematic structure makes a precise definition difficult. Although many scholars consider it a religious movement, its adherents typically see it as spiritual or as a unification of mind, body, and spirit, and rarely use the term New Age themselves. Scholars often call it the New Age movement, although others contest this term and suggest it is better seen as a milieu or zeitgeist.

December 21 is the 355th day of the year in the Gregorian calendar; 10 days remain until the end of the year.