One of the most ancient monumental sites in Peru, Cerro Sechin is located in the Casma Valley, 168 miles north of Lima. Discovered in 1937 by renowned Peruvian archaeologist Julio C. Tello, the site is best known for its megalithic architecture and engraved stone slabs, which depict graphic scenes of human sacrifice and death. Cerro Sechin is part of a larger group of sites known as the Sechin Complex, a group of contemporaneous settlements in the Casma Valley that exhibit similar monumental public and ceremonial architecture, and which practiced small-scale irrigation agriculture. All of the sites in the Sechin Complex were ideally situated on or nearby fertile agricultural land and their close proximity to communities on the coast provided easy access to marine resources.
Inhabited for much of the second millennium B.C., Cerro Sechin has been the most intensively studied site in the Sechin Complex. It covers roughly 50,000 meters squared and consists of a quadrangular three-tiered stepped platform flanked on each side by two smaller buildings. The platform was constructed in several stages using conical adobes, or large sun-dried bricks with broad circular bases and tapered points, which were then set into clay mortar and plastered over to form wall surfaces. A retaining wall, roughly 4.15 meters (13.5 feet) tall and containing nearly 400 granite sculptures, was added relatively late in the site's history and encircled the perimeter of the building. The stone sculptures, undoubtedly the most famous feature at Cerro Sechin, depict a possible mythological or historical scene in which a procession of armed men, probably important personages or warriors, make their way among the mutilated remains of human victims. Given the gruesome nature of the stone frieze, it seems likely that some degree of warfare, violence, and/or raiding existed among these early valley peoples.
Though little is known about Cerro Sechin's demise, the site appears to have been abandoned by 800 B.C., paralleling the decline of other important ceremonial and public centers on the Peruvian coast at this time.