El Caracol or the Observatory is so named because the inner staircase inside the round tower spirals upward resembling a snail. There is a stele, a picture tablet on the upper platform that dates the structure to 906 AD. Archeologists believe that this is where the Mayan gathered their information about the changes in the location of sun and other celestial bodies to predict seasons, weather patterns for agriculture and ritual purposes. They could even predict eclipses of the sun.

The observatory tower sits on a rectangular base and gives excellent 360degree views of the skies above the jungle scrub trees. Twenty sight lines of astronomical events (eclipses, solstice etc) can be found in the observatory. The three remaining windows in the tower were designed to track Venus in the night sky.

The stairwell leading up to the tower matches the Northern extreme of Venus and the Northeast and southwest corners of the rectangular building aligns to the summer solstice. Venus was considered the Sun's twin by the ancient Maya and a war God. Tracking Venus was important to the leaders because they would plan wars and raids around specific movements of the planet.

Chichén Itzá - The Observatory by Dorothy and Bill Bell