"Maya felt that we owed our existence to Venus who they called Kukulcan and their astronomer-priests repaid the debt with the blood of human sacrifice. Unfortunately, almost everything we know about the Maya’s sophisticated and complex system of Venus observations/ computations/prediction/worship comes from only four books that escaped the book-burning frenzy of the invading Christians. Included in this meticulously painted bark paper books is an abundance of astronomical information, including table of solar and lunar motions and table of Venus ephemeris, or table of motions, which is accurate for over a hundred years. The entire Mayan calendar, as were those of all Mesoamerican civilizations, was based on the 260-days Venus appearance interval. The 260-day Mayan calendar is still in use today in many areas of Guatemala. The 260-day Venus interval and the 365-day year come into phase every 18,980 days, or 53 years."