El Castillo (, Spanish for "the castle"), also known as the Temple of Kukulcan (or sometimes Kukulkan), is a Mesoamerican step-pyramid that dominates the center of the Chichen Itza archaeological site in the Mexican state of Yucatán. The building is more formally designated by archaeologists as Chichen Itza Structure 5B18.
Built by the pre-Columbian Maya civilization sometime between the 9th and 12th centuries CE, El Castillo served as a temple to the god Kukulkan, the Yucatec Maya Feathered Serpent deity closely related to the god Quetzalcoatl known to the Aztecs and other central Mexican cultures of the Postclassic period.
The pyramid consists of a series of square terraces with stairways up each of the four sides to the temple on top. Sculptures of plumed serpents run down the sides of the northern balustrade. Around the spring and autumn equinoxes, the late afternoon sun strikes off the northwest corner of the pyramid and casts a series of triangular shadows against the northwest balustrade, creating the illusion of a feathered serpent "crawling" down the pyramid. The event has been very popular and is witnessed by thousands of visitors at the spring equinox, but it is questionable whether it is a result of a purposeful design, because the light-and-shadow effect can be observed, without major changes, during several weeks around the equinoxes. Each of the pyramid's four sides has around 91 steps which, when added together and including the temple platform on top as the final "step",may produce a total of 365 steps (the steps on the south side of the pyramid are eroded) (which is equal to the number of days of the Haab' year).
The structure is 24m high, plus an additional 6m for the temple. The square base measures 55.3m across.
The construction of El Castillo, like other Mesoamerican pyramids, likely reflected the common practice of executing several phases of construction. The last construction probably took place between 900-1000 CE, while the substructure may have been constructed between 600-800 CE. Based on archaeological research, construction of El Castillo was based on the concept of axis mundi. It is thought that the space remained sacred regardless of the structure positioned on the location. When a temple or pyramid structure was renewed, the former construction was ritually destroyed, which involved resolving the space of spiritual forces to preserve its sacredness. It is estimated that this construction dates to the eleventh century CE. After all of the work was completed, an entryway was cut into the balustrade of the northeastern exterior staircase to provide access to tourists. The older, inner pyramid is referred to as the "substructure".
Inside the pyramid
In 1566, the pyramid was described by Friar Diego de Landa in the manuscript known as Yucatán at the Time of the Spanish Encounter (Relación de las cosas de Yucatán). Almost three centuries later, John Lloyd Stephens described with even more detail the architecture of the pyramid in his book Incidents of Travel in Yucatán (Incidentes del viaje Yucatán), published in 1843. At that time, the archaeological site of Chichén Itzá was located on an estate, also called Chichén Itzá, owned by Juan Sosa. Frederick Catherwood illustrated the book with lithographs depicting the pyramid covered in abundant vegetation on all sides. There are some photographs taken in the beginning of the 20th century that also show the pyramid partially covered by said vegetation.
In 1924, the Carnegie Institution for Science in Washington, D.C. requested permission from the Mexican government to carry out explorations and restoration efforts in and around the area of Chichen Itza. In 1927, with the assistance of Mexican archaeologists, they started the task. In April 1931, looking to confirm the hypothesis that the structure of the pyramid of Kukulkan was built on top of a much older pyramid, the work of excavation and exploration began in spite of generalized beliefs contrary to that hypothesis. On June 7, 1932, a box with coral, obsidian, and turquoise encrusted objects was found alongside human remains, which are exhibited in the National Anthropology Museum in Mexico City.
El Castillo is located above a cavity filled with water, labeled a sinkhole or cenote. Recent archaeological investigations suggest that an earlier construction phase is located closer to the south-east cenote, rather than being centered. This specific proximity to the cenote suggests that the Maya may have been aware of the cenote’s existence and purposefully constructed there to facilitate their religious beliefs.
After extensive work, in April 1935, a Chac Mool statue, with its nails, teeth, and eyes inlaid with mother of pearl was found inside the pyramid. The room where the discovery was made was nicknamed the "Hall of offerings" or "North Chamber". After more than a year of excavation, in August 1936, a second room was found, only meters away from the first. Inside this room, dubbed the "Chamber of Sacrifices", archaeologists found two parallel rows of human bone set into the back wall, as well as a red jaguar statue. Both deposits of human remains were found oriented north-northeast. Researchers concluded that there must be an inner pyramid approximately 33m wide, shaped similarly to the outer pyramid, with nine steps and a height of 17m up to the base of the temple where the Chac Mool and the jaguar were found.
The discovery of what appears to be a throne (referred to as the "Red Jaguar") in the throne room was previously assumed to have been decorated with flint and green stone discs, but recent research has determined the jaguar to be composed of highly symbolic and valued materials for ritualistic significance. The use of x-ray fluorescence (pXRF) was used to determine that the sculpture is painted red with a pigment that includes cinnabar, or mercury sulfide (HgS). Cinnabar was not in accessible proximity to Chichén Itzá, so the transportation of this pigment through long-distance trade placed a high value of this product. Additionally, the color red appears to be significant to Maya symbolism, and it is associated with creating life as well as death and sacrifice. Studies suggest that objects in Maya culture were imbued with vital essence, so the choice of painting the jaguar red may be a reflection of these beliefs, deeming the jaguar as an offering. The high-status associated with the cinnabar pigment and its red tone suggest that the jaguar was linked to ritual importance of closing a temple for renewal.
The four fangs of the Red Jaguar have been identified as gastropod mollusk shells (Lobatus costatus) using a digital microscope and comparative analysis from malacology experts from the National Institute of Anthropology and History, another valued resource that may have been traded into Chichén Itzá. The green stones were also analyzed and determined to be a form of jadeite. Jadeite was valuable economically and socially, and the acquisition and application of the material is indicative of the access Chichén Itzá had along its trade routes.
Archaeological studies indicate that the Red Jaguar is similar to other depictions of thrones found in murals (Temple of Chacmool), thus whomever was seated on this throne could have been accessing the point of axis mundi, which is essential to the elements and relationship to the cosmological system. The symbolic usage of materials related to the underworld and death also suggest that it acted as an offering for ritually closing the temple.
The location of the pyramid is aligned at the intersection between four cenotes: the Sacred Cenote, Xtoloc, Kanjuyum, and Holtún. This alignment supports the position of El Castillo as an axis mundi. The western and eastern sides of the temple are angled to the zenith sunset and nadir sunrise, which may correspond with other calendar events such as start of the traditional planting and harvesting seasons. However, the approximate correspondence with the Sun's positions on its zenith and nadir passages is likely coincidental, because very few Mesoamerican orientations match these events and even for such cases a different explanation is much more likely. Since the sunrise and sunset dates recorded by solar orientations, which prevail in Mesoamerican architecture, tend to be separated by multiples of 13 and 20 days (i.e. of basic periods of the calendrical system), and given their clustering in certain seasons of the year, it has been argued that the orientations allowed the use of observational calendars intended to facilitate a proper scheduling of agricultural and related ritual activities. In agreement with this pattern, detected both in the Maya Lowlands and elsewhere in Mesoamerica, the north (and main) face of El Castillo at Chichén Itzá has an azimuth of 111.72°, corresponding to sunsets on May 20 and July 24, separated by 65 and 300 days (multiples of 13 and 20). Significantly, the same dates are recorded by El Castillo at Tulum.
In recent years, the National Institute of Anthropology and History (INAH), which manages the archaeological site of Chichen Itza, has been closing monuments to public. While visitors can walk around them, they can no longer climb them or go inside their chambers. Climbing El Castillo was stopped in 2006, after a woman fell to her death. At the same time INAH closed the public access to the interior throne room.
Today "El Castillo" is one of the most recognized and widely visited pre-Columbian structures in present-day Mexico.
Additionally, researchers have discovered an enormous cenote (also known as a sinkhole) beneath the 1,000-year-old temple of Kulkulkan. The forming sinkhole beneath the temple is around 82 by 114ft and up to 65ft deep. The water filling the cavern is thought to run from north to south.
Researchers also found a layer of limestone about 16ft thick at the top of the cenote, on which the pyramid is sitting.
Recent archaeological investigations have utilized Electrical Resistivity Tomography (ERT) to examine the construction sequence of El Castillo. To preserve the site from potential damage, electrodes were placed non-traditionally as flat-based detectors around the quadrangle of the pyramid bodies of the pyramid. After each pyramidal body was tested, the data revealed two previous construction phases within El Castillo with a possible temple at the top of the second substructure. Determining the dates of when these constructions happened will provide time periods of when Chichen Itza may have been significantly occupied.