El Castillo, or The Castle, is probably the most well-known Mayan structure in the Yucatán Peninsula. This four-sided 23 meter/75 foot high pyramid is a truly impressive building. It must have been absolutely amazing to see it with its walls covered with the original stucco, painted in yellow, red, green and blue. The Mayans decorated their temples elaborately with murals and hieroglyphs. El Castillo stands as testimony to the Maya’s superiority as builders and mathematicians. The surfaces are massive, detailed, and sharp. The sophisticated Mayan calendar is incorporated in the architecture of this pyramid. One example of this is that the number of steps on each of the four sides is 91, adding up to 364, which together with the top platform equals the number of days in a year.
On the days of spring and fall equinox, the edge of the shadow from the sun, falls exactly on the corner of the pyramid, leaving one side in total sunlight and the other in total shadow. Furthermore, there is a shadow running down the north staircase taking the form of a snake; hence the carved snakeheads at the bottom of the staircase as well as the pyramid’s Mayan name Kukulkán, the plumed serpent god.
(photo via static.atlasobscura.com)