On each equinox (March 20 and again around September 23 every year), the main pyramid at Chichen Itza casts a shadow against itself. Connecting to the a snake head at the bottom of the pyramid, the shadow creates the body of an undulating snake for a two hour period around sunset. Yes, this is real. An incredible architectural feat considering the Maya people had yet to discover the wheel.
This photo was taken after waiting through an hour of overcast and a shadowless Mexican sky. Fortunately, the sun won out. The vision is one of the most impressive sights I have even seen. For those who may not make it to Mexico to witness one of the new seven wonders of the world, here is a preview.
My honorable mentions photos include a small handful of the five thousand locals and travelers who gather for the event, and one of the many sculptures on the grounds at Chichen Itza. This one is in the stadium, which offers more technical marvels and perfect acoustics.