Chichen Itza, (in Maya it means "At the edge of the well where the water lizards live") was one of the most important city-state in the pre-hispanic America. A classical Maya group founded a settlement, now known as Old Chichen in the area around 495 AD. They erected buildings in the Chenes and Puuc archaeological style. Around 900 AD, the Itzaes tribe arrived at Chichen and introduced a architecture with ornamental motifs in which the serpent god Kukulcan predominated.
This is one of the most remarkable buildings in Maya architecture, 78 feet high with a square base of 182 feet.
Around three in the afternoon during the spring and autumn equinoxes, the sun projects seven triangles of light into the balustrade on the northwest corner of the Castle forming a silhouette of a snake measuring 111 feet long. These triangles joins the stone serpent's head at the bottom of the stair. This effect is known as the "descent of Kukulcan" and is believed to be the start of the farming season.