Although there are lots of bizarre theories related to the end of the world, one of the most well-known has to do with the Mayan calendar. Many people wonder if, according to supposed predictions based on the calendar, the world will end on Dec. 21, 2012, which also happens to be the winter solstice.
What's bizarre about these fears is how people have distorted the information from the calendar. The Mayans actually use several intricate calendars, each with a different purpose. The one in question is known as the Long Count Calendar. It's a calendar just like any other calendar, and is used to keep track of time, except that it records a unique cycle that's 1,872,000 days long (instead of, say, our 365-day annual calendar). This long period is known as a Great Cycle, and to the Mayans, the end of such a cycle is a time for celebration, not for fear.
Theorists claim, however, that the Maya had some foresight into astrological happenings -- according to some Web sites, the beginning of the winter solstice will also coincide with all of the planets in our solar system lining up with the sun. Astronomers point out that these claims are false, however, and that it's impossible to predict accurately such an precise alignment.