Twice a year the sun hits the pyramid casting a shadow along the pyramids edge that appears to show a serpent climbing the pyramid in March and descending the pyramid in September.
Our guide also showed us that if you stand at the foot of the pyramid and clap the echo comes back to you as a piercing shriek. (believed by the Mayans to be an eagle) supposedly if a person were to stand at the top step of the pyramid and speak in a normal tone of voice it could be herd at ground level for some distance.
Iguanas also reside among the ruins.
Pictured below is believed to have been a throne.
Below is called El Caracol believed to be an Observatory. The observatory dome of windows aligned with major certain stars on specific dates.
I'm not exactly sure how this game was played but our guide told us it involved passing a hard rubber ball through the scoring ring mounted on the wall. Supposedly once the game was won the winning team captain presented himself to the losing team captain and was decapitated by him. This was supposed to be a great honor and guaranteed him a place in heaven.
Below is a model of what the city may have looked like.