The Pyramid of Kukulkán at Chichen Itza

Two of the sides of the pyramid have been completely restored, the other two were left as they were.

The pyramid was linked to the Mayan Calendar and Mayan astronomy. Each side had originally 91 steps, adding the platform at the top as a final step there are 365 in total one for every day of the year. At the spring and autumn equinox the shadow of the sun on the stairs creates an illusion of a snake slithering down the steps.