Tiwanaku

Tiwanaku or Tiahuanaco, site of pre-Inca ruins in Bolivia, southeast of Lake Titicaca. Its location, in the Andes at about 3,800 m (about 12,500 ft) above sea level, made Tiwanaku the highest city in the ancient world. An earlier view that Tiwanaku was a ceremonial center that was used only periodically by the Aymara people, believed to be the city's founders, has been disproved by recent investigations in and around the site, which show it to have been a populous urban center supported by a sophisticated system of raised-field agriculture, well adapted to producing crops at high altitude. The few radiocarbon tests indicate founding dates older than ad 300. Certain structures were apparently left uncompleted when, for some unknown reason, all work ceased about ad 900.

The masonry at Tiwanaku reveals some of the most skillful workmanship in South America. Certain stone-linking methods indicate the earliest use of metal for structural purposes in the western hemisphere. The Akapana, the largest unit at the site, is the remnant of a terraced pyramid about 15 m (about 50 ft) high and 152 m (500 ft) on each side. The most famous monument at the site is the Gateway of the Sun, an enormous sculpture carved from a single 9 metric-ton block of andesite and decorated with a distinct style of low-relief frieze. The meaning of the intricate symbolism in the decoration is uncertain. Another unit, the Kalasasaya, is a large square area delimited by upright monoliths (single blocks of stone), which appear originally to have formed part of a continuous wall. A semisubterranean temple nearby has been restored. Anthropomorphic statuary, mostly in characteristically symmetrical, stiff style, has also been found at the site.