Chichén Itzá

Chichén Itzá flourished as a major Maya political and economic centre from around 600 to 1200 CE, blending Maya and Toltec architectural styles. Its central pyramid, El Castillo (the Temple of Kukulcán), is built with 91 steps on each of its four staircases — 364 in total, plus the temple platform, equalling the 365 days of the solar year. On the spring and autumn equinoxes, the setting sun casts a series of triangular shadows down the northern staircase that combine with a carved serpent's head at its base to create the illusion of a feathered serpent — Kukulcán — descending the pyramid.

A clap of the hands at the base of El Castillo's staircase produces a chirped echo that acoustic researchers have compared to the call of the resplendent quetzal, a bird sacred to the Maya — though whether this effect was deliberately engineered remains debated. Roughly 300 metres north of the pyramid lies the Sacred Cenote, a natural sinkhole 60 metres in diameter into which the Maya cast offerings — and, according to early Spanish chroniclers and subsequent dredging that recovered gold, jade, and human remains, occasional sacrificial victims — to appease the rain god Chaac during droughts.