It's almost time, just slightly more than three days, before we celebrate Christmas once again. Today it's the Winter Solstice.
This occurs on the shortest day and longest night of the year, when the sun's daily maximum elevation in the sky is the lowest. Since the winter solstice lasts only a moment in time, other terms are often used for the day on which it occurs, such as midwinter, the longest night or the first day of winter.
This year there is an added note of interest because some people think that the world will come to an end on this occasion and that this is predicted in the Mayan calendar.
The Mayan calendar moves in cycles with the last cycle ending in December 2012. This is often interpreted as "the world will end on 21 December 2012, at 11:11 UTC".
The last day of the Mayan calendar corresponds with the Winter Solstice (or December Solstice), which has played a significant role in many cultures all over the world.
The Maya didn't invent the calendar, it was used by most cultures in pre-Columbian Central America – including the Maya – from around 2000 BC to the 16th century. The Mayan civilization developed the calendar further and it's still in use in some Maya communities today.