It turns out this calednar was only good for a mere 5-thousand years... Dating back to around 3100 BC - there are still a couple others that are still running.
But does the end of the Mayan long count calendar mean a big show - volcanos erupting.... earthquakes knocking down buidlings???
Experts say no.
Chris Jannsen teaches astronomy at Wausau West. "There's a prophesy that a planet will hit earth.", he says, "No one has seen that planet. Another is that there will be planetary alignment - that's not happening. It's all make-believe."
But here's the thing. Even though one of their calendars is coming to an end, the Maya - they still exist - they see it as the begining of a new cycle.
One thing is for certain - we'll all know for certain when the calendar runs out at the winter solstace at 5:11 AM December 21st.