Paul Jackson and his wife have just returned from their honeymoon, which consisted of two weeks in Mexico followed by two weeks in Scotland. While in Mexico, they went on a day trip to see the thousand-year old Mayan ruins at Chichén Itzá. But they didn't go on just any day -- they went on the Autumn Equinox, when the direction of the setting Sun is exactly due West, making it a special day in the calendar. And as everyone knows, the Mayans were obsessive about the calendar.
The Mayan Prophecies (1995): "Twice a year, at the equinoxes, the Sun plays an amazing trick, which must have seemed like a miracle to anyone not initiated into its secrets. During the afternoon on these two days, shadows are cast on the balustrade which take the form of moving serpents gliding down the side of the pyramid. We can only speculate on what this symbolized, but perhaps it seemed to the onlooker as though some magical, ghostly Quetzalcoatl were in a sense coming back to life."
Although much newer than the pyramids of Egypt, or even the ruins of ancient Greece and Rome, Mayan archaeological sites like Chichén Itzá were lost in obscurity until comparatively recently. It was only in the early part of the 20th century that the scrub and overgrowth was cleared from the Temple of Kukulkan, and the mysterious shadow effect was rediscovered. Now, of course, with 2012 looming, everyone has heard about the Mayans and their alleged prophecy concerning the end of the world (Gilbert and Cotterill's book, mentioned above, scooped almost all the other writings on this subject by more than a decade). If you believe in the prophecy, and you want to see the shadow of the serpent god, you'll have to hurry. There are only two equinoxes left -- in March and September next year!
A full view of the pyramid, seen earlier in the day, is shown below.