The Mayan calendar, also known as the Long Count, is a complex system used by the Maya to track time based on astronomical observations and astrological significance. It contains three main elements - a base date of August 11, 3114 BC, grouping time into multiples of 13 and 20 like the 260-day cycle, and an astrological component. The Long Count precisely measures time in cycles, with the current cycle ending on December 21, 2012 when the winter solstice aligns with the Milky Way, an important date in Mayan mythology marking the end of the current world age and the precession cycle of around 25,695 years.