Located near the town of Casma, 330 km (210 miles) north of Lima, on Peru's Pacific coast, in the Department of Ancash, the Sechin Archaeological Complex was the capital of a pre-Inca culture - known as the Sechin-Casma - that proliferated in the area from approximately 1,800 - 900 BC, and possibly earlier.
The complex covers around 10.5 square km (4 sq. miles) and includes four separate sites - Sechin Alto, Taukachi-Konkan, Cerro Sechin, and Sechin Bajo. They all share architectural traits and coincidental orientation, so it is thought that they formed one large, continuous settlement along the River Sechin, a tributary of the Casma.
Sechin Alto, a flat-topped pyramid measuring 300m (984ft) in length, by 250m (820ft) in width, and 35m (115ft) in height, forms the centrepoint of the complex. The exterior of the pyramid was dressed with giant, granite blocks, measuring 1.5m (5ft) in height and weighing up to two tonnes.
Estimated to have been built between 1600 and 1400 BC, it was the largest construction in the Americas at the time and remains the biggest pre-Colombian monument in Peru. On account of its size and location, it is assumed to have been the administrative centre for the region.
Taukachi-Konkan is a set of mounds and plazas that lie to the northwest of Sechin Alto, covering an area of roughly 1,250m (4,100 ft) by 500m (1,600 ft). And like Sechin Alto, most of the structures are constructed of granite blocks, from local quarries.
Cerro Sechin is the most intensively-studied site in the Sechin Complex, whose gruesome friezes have led archaeologists to define Sechin-Casma culture as war-like and aggressive.
It consists of a quadrangular, three-tiered platform, flanked on either side by two smaller buildings; and is thought to have been in use for much of the second millennium B.C., before being abandoned around 800BC ... for reasons that are not yet understood.
Cerro Sechin is best known for some 300 etched bas-reliefs, with graphic imagery that includes axe-wielding warriors, decapitated and mutilated victims, and their body parts. Not surprisingly, given the proximity of the rich waters of the Pacific Ocean, depictions of fish are also present.
The final archeological group within the complex, Sechin Bajo, recently came to attention as a result of the 2008 discovery of a circular plaza, made of rocks and rectangular adobe bricks, that was dated using radiocarbon techniques to 3500 BC. A nearby 2m (6.5 ft) tall frieze was dated at 3600 BC.
This meant that they are the two oldest examples of monumental architecture discovered so far in the Americas, even older than Caral, of the neighbouring Norte Chico culture, and the oldest urban settlement of the New World.
It also turned on its head the previously-held theory that Chavin culture had influenced Sechin-Casma, as it was now seen that the latter pre-dated the former ... by thousands of years!
The Max Uhle Site Museum contains many of the artifacts encountered during excavations, as well as an overview of the history of Casma town.
How to visit: the tourism infrastructure in this region of Northern Peru is still underdeveloped, but being on the PanAmerican Highway between Lima and Trujillo, it is only roughly a four or five-hour drive from either, and serviced by many inter-city buses.
For those wishing to see Sechin, along with the nearby archeological ruins of Chankillo and Las Aldas, we recommend spending a night in Casma, where there is simple accommodation, and taking a guided tour that departs in the morning.
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