Chichen Itza in Yucatan, Mexico, where this Mayan temple is situated was one of the greatest of the Mayan cities. It was founded in 750 AD and continually occupied by various Mayan dynasties until the beginning of its decline as a major political centre around 1250. However Mayan communities continued to live there until the arrival of the Spanish in the 16th century AD. The Kukulkan temple seen here (also known as El Castillo) was dedicated to the Mayan feathered serpent deity of the same name. The pyramid stands at 78 ft (24m) high. I will certainly show more detailed images of this and other ruins and restored ancient Mayan buildings at Chichen Itza and other Mayan sites in due course. Edit: as pointed out by silversolo below, each of the four sides of the pyramid has 9 tiers of 9 steps each,making 81 x 4. Add to that the temple platform at the top and you get 365, the number of days in a solar year. I might also mention that each of the sculptures at the foot of the central balustrades represent the head of Kukulkan the serpent god and twice a year during the spring and autumn equinoxes, due to the way the pyramid was constructed the late afternoon sun casts a series of triangular shadows against the northwest balustrade, creating the illusion of a feathered serpent "crawling" down the pyramid.