Chichén Itzá was first settled around the 6th century AD beside two large cenotes, natural wells formed in the limestone that ensured a supply of water in an arid region. The oldest buildings, south of the main plaza, are in the Puuc style and include the Nunnery complex, the Church, the Akab Dzib, and the Chichan Chob, built between the 6th and 10th centuries.
From the 10th century onward, the city absorbed elements from central Mexico associated with the Toltec tradition — a fusion that, for UNESCO, makes Chichén Itzá the most important archaeological vestige of the Maya-Toltec civilization in Yucatán. This period produced El Castillo, dedicated to Kukulcán, as well as the Temple of the Warriors, the Group of the Thousand Columns, and the Great Ball Court.
According to UNESCO, there is no record of major construction after the 13th century, and the city declined rapidly from around 1440. When the Spanish arrived in the 16th century, the great Maya centers, Chichén Itzá among them, were largely abandoned — yet the site remained sacred to the Maya.
Excavations began in the 19th century, and in 1904 the American Edward H. Thompson started dredging the Sacred Cenote. Protected under Mexico’s 1972 federal law on monuments and declared an archaeological monument by presidential decree in 1986, Chichén Itzá was inscribed on the World Heritage List in 1988 and, in 2007, announced in Lisbon as one of the New Seven Wonders of the World.
Chichén Itzá’s architecture is in dialogue with the sky. Each of El Castillo’s four staircases has 91 steps; together with the step of the top platform, they total 365, the number of days in the solar year. On the days around the equinoxes, seven triangles of light and shadow fall across the balustrade of the north staircase and, joined to the serpent head carved at its base, suggest the descent of Kukulcán.
For INAH, the phenomenon reveals the high level of astronomical and architectural knowledge attained by the Maya — expertise also associated with El Caracol, the circular observatory whose spiral staircase gave it its name. Water had a sacred dimension: the Sacred Cenote received offerings to the rain god, Chaac, and the dredging begun in 1904 brought to light skeletons and sacrificial objects.
At the Great Ball Court, six reliefs carved along the walls appear to depict the game’s victors, and the acoustics allow a whisper to be heard about 46 meters away. The tradition lives on: the 2025 spring equinox drew 32,872 people, according to INAH. And, as UNESCO notes, Yucatán is the only Mexican state where two institutions — INAH and the Patronato CULTUR — take part in managing the archaeological sites.
