Thanks baynut. This 'blog is, like the Giles, Giles, Fripp album in 1968, a bit of cheerful insanity, IOW, I will be going back for more. :')
The Mayans built their complex calendar to track various celestial objects which each keep their own time, and the "cycle" is based on the math of when all of them happen to finish at the same time. Naturally, this is a long period of time.