What is mean by MAYAN Calender?

Mayan are the Ancient and most advanced scientific South American indians they were more advanced than any other tribe and figured out the seasons months by looking at nature it is very similiar to the calander than ours and they predicted certain events and occurences that would take place on earth. Like the end of the world and other events.

This might help: http://en.wikipedia.org/wiki/Maya_calendar