This building, one of the few circular structures built by the Maya, is believed to have been used for astronomical observations, throught openings in the top of the tower.
The so-called Caracol or Observatory is a structure built in the form of a larger circular tower set on a platform with a central staircase. The base is set on another rectangular platform, decorated with a cornice of rounded corners on the upper part. The Caracol is really built of three superimposed buildings.
The first part of the cylindrical tower is formed by two concentric walls which enclose a pair of circular chambers each with four doorways.
The second level comprises the cornice of the first level and a second, narrower one, which frames a frieze. Above the doors, the frieze has a mask o Chaac and a seated figure, framed with motifs made of feathers and serpents.
The third and fourth parts of the tower have deteriorated, but a series of openings or windows can still be glimpsed which perhaps served for making astronomical observations.
On the west side of the larger base there is a staircase whose balustrades are adorned with intertwining serpents´ heads.
The total height of the monument is 75 feet. The structure was constructed during the first period of the Military city.
The Maya Studied the sun, the moon and Venus, and their observations included some visible bodies such as Mercury, Mars and other stars.
Their priests, the greatest astronomers of the time, succeeded in calculating solar and lunar eclipses, the rising and setting of Venus and the movements of stars and planets, as well as the solar year, with great accuracy.
Even today, scientists are amazed at the development of Mayan astronomy. For the ancient Maya, astronomy and cosmogony were closely linked in their mythical conception of the universe.
Known as the “Lords of Time”, the Maya were unique in elevating to the rank of gods not only the idea of time, but also the periods into which it is divided. They represented time as supernatural beings whose mission was to maintain order in the universe. The Mayan gods of time completed their life cycle in a constant circular movement beginning with their birth, developing with the manifestation of their characteristics, and finishing with their death. They were then re-born and a new cycle of birth and death was begun.