Mayans and the Equinoxes
The ancient mayans, naturally good observers, didn’t just dedicate their atention to the stars, but they realised the station changes and the correspondence of important agricultural moments dates with the sun’s position and moments and with other astrological events. Understanding it was not enough to observe such phenomena, but that they should register and calculate them in order to establish a cronological rythm, they invented signs to represent sky planets, time periods and their respective records. Hence they created a writing system, mathematics and finally the Tzolkin Calendar, more accurate than the one we presently use.
Normally, Mayan buildings were oriented towards the cardinal points and towards planets and stars, Sun, Moon, Mars and Venus principally. Among their archaelogical legacy we can find Dzibilchaltun, Uxmal, Chichén Itzá y Tulúm (this last one only 2 hrs away from Cancún), each of them a great example of their design and building creativity. All of them being in perfect coordination with the specific natural phenomenon they wanted to highlight, as is the case with the Equinoxes.
The equinox is the day when the sun crosses the ecuator line and makes the day and night to last exactly the same time. This happens twice a year: march 21, and september 23. The equinox days were important for mayans and other ancient earth-related cultures because they indicate the beggining of the sowing and harvesting cycles. 
Mayans made records of this events in the buildings that have a 17 degree north orientation. The most representative one of this buildings, the one where they used all their astronomy, mathematics, cronology, geometry and religious knowledge is Kukulkan’s Pyramid, or “The Castle” at Chichen-Itza, where every year thousand gather to witness the greatness of the mayan legacy. It is here where skies, earth, science and magic get together. It is here where, on the northern stair of the building, a snake-like projection of seven light triangles can be seen as a result of the shadow cast over the building’s nine platforms.
The vision is one of a serpent, the God Kukulkán, the most important deity to the mayans, who slowly descends from the top to the base of the pyramid. This image lasts approximately 30 minutes, and it is the moment everybody awaits to receive cosmic energy.
It is so amazing and special, that event the NASA records it every year, so the entire world can be witness of this wonderful archaeological-astronomical event.
