Cahuachi was the major ceremonial center of the Nazca culture from 1 CE to about 500 CE. The "ciudad perdida" contains over 40 mounds topped with adobestructures. The permanent population was quite small. The town was apparently a pilgrimage center that grew its population during the ceremonial events. These events probably involved the Nazca lines.
"Cahuachi's most famous monument is the Great Pyramid, which hogs the skyline and casts an eye over the Nazca Lines, the geoglyphs which have made the culture so famous. As with most buildings in the city, the pyramid looks like a giant maze thanks to the winding ceremonial staircases which lead to its summit.... Many ceramics and other ceremonial items, such as fabrics and paintings, have been found in Cahuachi. ... Like many pre-Columbian American cities, Cahuachi was mysteriously abandoned, around 500 AD."
http://heritage-key.com/site/cahuachi
Thanks to Wikipedia and Ed88!
