Becky and I woke up early and hiked a few miles to the Chichen Itza ruins. We entered and it was totally quiet, not many people there at all. We walked around and viewed the ruins. I was able to give her the tour since I had already been there.
As it turns out the light and shadow effect of the Equinox on the pyramid is only visible as the sun is setting, so after seeing everything we had some lunch and took a break, returning later to see the phenomenon. Many tourists arrived by the bus load to see it as well. What happens is that as the sun sets on the equinox the shadows from different levels of the edge of the pyramid climb a flat banister wall creating a serpent of light that aligns with a stone serpent head at the base of the pyramid. At around 5:00 you could see the serpent start to take shape, and at 6:30 it was supposed to be in the exact position. Now this all relies, obviously, on a clear sky and hard shadows. Unfortunately, about five minutes before the serpent was in perfect position, the sun sank behind some thick dark clouds, never to return. It started to rain not long after, and that was the end of the show.
We were both a little disappointed, but still just happy to see as much of it as we had. It is truly amazing that the Mayan people, around AD 500, not only had detailed knowledge of the cosmos, but also the ability to construct a massive pyramid that is essentially a giant calendar that maps out the movement of the Earth and the planets. They did this all with out the use of the wheel!
We headed back to the hotel to relax and have some dinner, with plans to leave on an 8am bus to Tulum the next morning.