chuckyj1 on 28 December 2012
http://jameswatt.me/2012/03/07/mayan-calendar-and-the-gregorian-leap-year/
"The Mayan calendar is very inaccurate when calculating years. Not only did they not account for leap years, they were completely wrong about how many days were in a year. The Mayan “tun” is 360 days long, equivalent of 0.986 years."
Not only did they NOT account for Leap years, but they also only accounted for 360 days! a year, which would have made their calendar obsolete a long time ago.
