El Caracol, also known as "the observatory," presents us with some of the most insightful information as to the skywatching activities of the Mayans. El Caracol seems to be carefully aligned with the motions of Venus, a planet which held great significance within the Mayan culture as it was considered to be the twin to the sun and a God of war. Mayan leaders planned appropriate times for battle by the positions of Venus. El Caracol is the only building out of line with the others at Xichen Itza with its grand staircase facing 27.5 degrees to the northwest - nearly a perfect match to the most northern position of Venus. In addition, a diagonal formed by the northeast and southwest corners of the builting align to the sunrise of the summer solstice and sunset of the winter solstice.
The afore-mentioned Catholic church built of the bricks of El Castillo removed by the Franciscans - Piste, Yucatan, Mexico