The Band of Holes

In Peru’s Pisco Valley, there is a strange alignment of thousands of shallow pits. The pits are arranged in a narrow band about 14 to 20 meters wide, that run up a hill for about 1,500 meters. Their purpose or function is a mystery.

The feature is locally known as Monte Sierpe (serpent mountain) or Cerro Viruela (smallpox hill). It is also called by the name Band of Holes.

Photo: Gustavo Rios

Cerro Viruela is a relatively unknown site even among archeologists who have been working in Peru for decades.

The site first came to media attention in the 1930s after aviator Robert Shippee published an aerial photograph in the National Geographic. Since then, very few archeologists have visited the site. In 1953, American explorer Victor Wolfgang von Hagen surveyed the area and described the pits as “graves” but empty. He estimated that there are about 5,000 such graves in the area.

Archaeologist John Hyslop speculated in his 1984 book The Inka Road System that the circular structures may have been used for storage, similar to the ones found on the Peruvian south coast in the sites Quebrada de la Vaca and at Tambo Colorado.

The holes are about three feet across and 20 to 40 inches deep. They were made in various ways, some dug into artificial mounds of soil and others made up of small rock structures on the surface. The band is divided into several unique groupings, which they called blocks, each of which have different patterns of holes.

Satellite view of Band of Holes.

In 2015 a team of archeologists from the University of California made a detailed study of the site, using a drone to create a map of the Band of Holes, which they estimated is made up of between 5,000 and 6,000 depressions. The archeologists did not find any direct evidence, but the presence of an Inca road nearby, a series of colcas (Inca-period storage houses), along with the discovery of Inca-period pottery near the band, seem to suggest that the Band of Holes date to sometime around the 15th century, after the Inca Empire conquered the Chincha people. They also felt the holes were once used to store something, but just what and why still wasn’t clear.

Charles Stanish, an expert on Andean cultures who led the research by the University of California, believes that the holes were dug to measure produce that farmers had to deliver to the Inca kings as tribute.

The Band of Holes is located only four miles from Tambo Colorado, a massive fifteenth-century Inca administrative center built above the agriculturally productive Pisco Valley. The Band of Holes is constructed along a road leading from the valley floor to Tambo Colorado. “It’s the perfect place to stop, measure your produce, and make sure you have the proper amount of tribute,” says Stanish. He thinks that each individual block of holes might have belonged to a different extended family, or ayllu, that would have been a distinct tax-paying group. “You may have had each social group come up and fill up their block with squash, maize, or any other produce in front of the state’s accountants, who could have been keeping a tally with khipus. The goods could have then been taken to Tambo Colorado, or wherever else the authorities wanted to take them.”

Photo: COSTUMBRES PERU TOURS

If the Band of Holes was a means to measure tribute payable to the Inca Empire by a family, why no parallel exists in any where else of the empire? Stanish explains that Inca state was a far-flung empire, and its separate regions retained some autonomy. The Band of Holes may be a local solution to the specific problem of measuring tribute devised by the administrators in the Pisco Valley. “The farther you get from the big Inca centers and Machu Picchu, the more local influences become apparent,” says Stanish. “Monte Sierpe may have satisfied a very local need.”

Jean-Pierre Protzen, a specialist in Inca architecture at the University of California, disagrees. Protzen, who has spent years working at Tambo Colorado, feels the Band of Holes is not contemporaneous with the massive Inca center. “There are other, earlier major sites close to Monte Sierpe that could have been associated with it,” says Protzen. He thinks the holes may have been used to store guano, an important fertilizer.

The fact is, we still don’t know who created the holes or why.