Scottmsg gave an excellent explanation of all of this. I studied this about 20 years ago in a course on archeoastronomy. Back then (and apparently still today) one of the big questions was the alignment of our calander to the Mayan's.

One of the things I always found interesting was how the Mayans counted the days of the year by the interaction of the Tun and the Winal. We go Month and then count days in that month (January 1, 2, 3). If you represent Tuns as letters and Winals as numbers, their scheme was more like A1, B2, C3, D4..... R18, then A19, B20, C1, etc. (I hope I worked that out right). Think of it as a gear with 18 teeth meshing with a 20-teeth gear. That gives 360 days. They knew that this was not the correct length of the year and had an equivalent of leap days (including the notion that 365 was not right either).

They also made wide use of base 20 counting schemes in their calendars and were pretty consistent at putting dates on their writings. There is also evidence that their calendars were advanced enough for such things as tracking the phases of Venus (important in their religous beliefs) and predicting lunar eclipses.

But all that means is that there were careful observes of the world and kept good notes. I have no belief they knew anything more than we do abou the end of the world. While their decendants are alive today, their main civilization ended about 1000+ years ago, so I guess you could say their world already ended.

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At night the stars put on a show for free (Carole King)