If I asked you to describe the function of a calendar, your initial response would probably be to describe the device as a means of keeping your weekly or monthly appointments. Moving beyond this somewhat limited scope, let us see the calendar for what it really is—a tool, designed to determine (as accurately as possible) the Earth’s annual orbit around the Sun.

Our modern Western calendar was first introduced in Europe in 1582. It was based upon the Gregorian calendar, which calculated Earth’s orbit around the Sun to take 365.25 days. This incorporated a very small plus-error of 0.0003 of a day per year, quite impressive for scientists of the 16th century.

The Maya derived their calendar from their predecessors, the Olmec, a mysterious people whose origins can be traced back some 3,000 years. Imagine for a moment, that you are living thousands of years ago. Then are no televisions or radios, telephones, or watches, and it is your job is to chart the stars to determine the passage of time equating to one planetary orbit. Somehow the Olmec, without precision instruments, calculated the solar year to be 365.2420 days, incorporating an even smaller minus error of 0.0002 of a day.

Let me restate this so you can grasp the implications: The 3,000-year-old Mayan calendar is a 10,000th of a day more accurate than the calendar the world uses today!

There’s more. The Mayan solar calendar is but one part of a three-calendar system. A second calendar, the “ceremonial calendar” operates concurrently, consisting of 20 months of 13 days. The third part, the “Venus calendar” or “Long Count,” was based on the orbit of the planet Venus. By combining these three calendars into one, the Maya were able to forecast celestial events over great expanses of time, not just thousands but millions of years. (On one particular Mesoamerican monument, an inscription refers to a time period dating back 400 million years.)

Impressed yet?

The Maya believed in Great Cycles, periods of time that registered the recorded creations and destructions of the world. The calendar recorded the five Great Cycles or Suns of the Earth. The current and last cycle began on 4 Ahau 8 Cumku, a date corresponding to August 13, 3114 BC, considered by the Maya to be the birth date of the planet Venus. This last Great Cycle is predicted to end with the destruction of humanity on 4 Ahau 3 Kankin, a date determined as December 21, in the year 2012—the day of the winter solstice.

The Day of the Dead.

How convinced were the Maya that their prophecy was true? After the departure of their great teacher, Kukulcan, the Maya began practicing barbaric rituals involving human sacrifice, cutting out the hearts of tens of thousands of men, women, and children.

The ultimate sacrifice—all to forestall the end of humanity.