The Mayan calendar is a system of different calendars and almanacs used by the Mayan civilization in Central America during the pre-Columbian period. These calendars were synchronized and closely integrated in a complex way to form a wider and longer-term cycle. In 2012, American archaeologists discovered the oldest Mayan astronomical table in the Mayan cultural site in Guatemala, which recorded astronomical phenomena and calendars. The calendar has continued to exist for more than 7,000 years, overturning the "2012 Doomsday Theory".