Hundreds of years ago, anyone descending the valley toward the site of Cerro del Gentil at the time of the winter solstice would have seen the sun set directly behind its adobe pyramid, framed by two long lines of stones converging on the event.
     The two stone lines are about 2 kilometres east-southeast of the pyramid, and run for approximately 500 metres. According to researchers, along with the pyramid the lines form "part of a single architectural complex, with potential cosmological significance, that ritualised the entire pampa landscape."
     The flat-topped pyramid is 5 metres high, was built sometime between 600 and 50 BCE, and re-occupied somewhere between 200 and 400 CE. Finds near the pyramid include textiles, shells and ceramics. The stone lines were constructed between 500 BCE and 400 CE.
     About 50 of these stone lines have so far been found in a flat, dry area near the pyramid, with the longest running for about 1500 metres. The lines are straight, and made out of rock - unlike the Nazca Lines in southern Peru, which were etched into the earth by removing the topsoil, and include depictions of animals and plants.
     Interspersed with the lines researchers have found more than 200 cairns, the largest about 15 metres in diameter. The stone lines and cairns appear to be connected with four nearby settlements - two with large pyramids, and one with a mound - which would have supported around 1000 persons.
     According to Charles Stanish - a professor at the Cotsen Institute of Archaeology, University of California, Los Angeles - "We have lines that run to pyramid complexes, and that's significant, because in the big Nazca pampa and in the Palpa pampa, we don't find that pattern as obvious."
     The team plan to excavate at the Cerro del Gentil pyramid, search for more stone lines, settlements, and features, and try to determine precisely when they were built.

Edited from Yahoo! News, LiveScience (6 May 2013)