- Huge band of holes stretches several miles north from Peru’s Pisco Valley
- Archaeologists estimate there may be up to 6,000 of the shallow pits
- Aerial photographs have revealed they are arranged in regular patterns
- Experts say they were used as part of a complex Inca accounting system
In an enormous band stretching several miles across an arid plateau in southern Peru, a mysterious line of shallow holes are perhaps one of the least well-known legacies of the Inca Empire.
The band of holes, which extends from north to south across the Pisco Valley in Nazca, Peru, like the world’s most uneven road, have baffled archaeologists for decades.
But archaeologists believe the narrow pockmarked piece of landscape may have been used to help the Inca rulers collect and collate their taxes.
The rock-lined holes, which are around 3ft-wide (1 metre) and up to 40 inches (101 cm) deep, would have helped keep precious food cool and dry in the harsh climate, the researchers said.
Crucially, however, the holes would also have allowed the authorities to keep track of who or where the food tributes had come from.
Professor Charles Stanish, an archaeologist at the University of California Los Angeles, believes food in the holes was then allocated to people in the Inca state – a nearby storehouse called a colca.
Together with his colleague Henry Tantalean, he has found Inca pottery dating to shortly before the time when the Spanish invaded Peru in 1532.
Using drones, the team collected aerial images and have created a new map of the Band of Holes, which it estimate is made of more than 6,000 depressions before they peter out.
They found the layout of the holes was remarkably similar to the checkerboard pattern used in an Incan colca at Inkawasi, around 160 miles (258km) to the north.
Researchers there believe this was used to measure specific amounts of tribute owed by each farmer or family, which were then recorded a knotted string called a khipu.
Professor Stanish said the band of holes also appears to be constructed alongside a road leading from the Pisco Valley floor to Tambo Colorado, a massive Inca administrative centre.
Speaking to Archaeology magazine, he said: ‘It’s the perfect place to stop, measure your produce and make sure you have the proper amount of tribute.
‘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.’
While the team has yet to find any khipu at the band of holes, or remains of any crops that may have been stored in the holes, it believes its theory is compelling.
The band of holes has been largely overlooked by archaeologists in the past, partly because they look relatively unassuming from ground level.
However, viewed from the air, the band can be seen stretching for miles towards the north, over the rolling desert landscape.
Professor Stanish himself knew nothing about the holes despite having spent nearly 30 years excavating a site in the nearby Chincha valley just 10 miles (16km) away.
It was only when a member of the public contacted him to ask about the holes and he looked it up on Google Earth that he realised something had been overlooked.
The site was first documented in 1931 by aerial photographers and the few archaeologists who visited the site concluded the holes had been dug to provide storage.
But the reason why this was done has remained a mystery and the holes have been largely overshadowed by the more famous Nazca Lines which can also be found in the area.
There are also some that claim the holes were initially dug by a more ancient culture up to 2,300 years ago but then were adapted for use by the Inca.
Some claim the holes were built as a form of geoglyphic art much like the Nazca Lines themselves.
Dr Jean-Pierre Protzen, who specialises in Inca architecture at the University of California, Berkeley, believes the holes predate the Inca and may have been used to store guano as a fertiliser.
But Professor Stanish added: ‘If I’m right, then we’re going to have to think differently about a lot of sites that have been regarded as strictly ritual.
‘We could be on the cusp of a whole new understanding of Inca accounting.’
THE NAZCA’S MYSTERY HOLES
Further to the south, close to the town of Nazca, strange spiraling holes dotted across the arid valleys of southern Peru have puzzled generations of archaeologists.
But researchers believe they may have solved the mystery of the holes, known as puquios, with the help of satellite images and data.
They claim the holes formed part of a ‘sophisticated’ hydraulic system that allowed the ancient Nazca civilisation to retrieve water from underground aquifers.
The Nazca culture, which flourished around 100BC to 800AD, were the same people who created the vast geoglyphs on the featureless landscape, also known as the Nazca lines.
It is thought they operated by channelling wind into the earth down the corkscrew holes and into a series of underground canals that carried water from aquifers.
This influx of air kept the water moving along the canals, forcing it out into the network of channels in areas where it was needed.
THE MYSTERY OF PERU’S NAZCA LINES
The geoglyphs, more commonly known as the Nazca Lines, were apparently first spotted in 1939 when a pilot flew over the Nasca planes of the Peruvian coastal highlands – although its likely they were seen by locals on hill tops much earlier.
They were designated as a UNESCO World Heritage Site in 1994 and the area stretches 50 miles (80km) between the towns of Nazca and Palpa, about 250 miles (400km) south of Lima.
Some 700 geoglyphs are thought to have been drawn by the ancient Nazca people between the first and sixth centuries.
The Nazca Lines are drawn into lighter coloured strata which contrasts with darker gravels on the plain.
Many of the images also appeared on pottery and textiles of the region. Other drawings represent flowers, plants, and trees.
A second is made from lines and more basic shapes such as spirals, triangle and rectangles.
Archaeological surveys have found wooden stakes in the ground at the end of some lines, which support theory the ancient people used simple tools and surveying equipment to construct the lines.
Most of the lines are formed by a shallow trench with a depth of between four inches (10cm) and six inches (15cm), made by removing the reddish-brown iron oxide-coated pebbles that cover the surface of the Nazca desert and exposing the light-coloured earth beneath.
This sublayer contains high amounts of lime which has down the years hardened to form a protective layer that shields the lines from winds and prevents erosion.
Contrary to the popular belief that the figures can only be seen from the air, they are actually visible from the surrounding foothills.
Paul Kosok, from Long Island University, is credited as the first scholar to seriously study the Nazca Lines.
He discovered that the lines converged at the winter solstice in the Southern Hemisphere.
Along with Maria Reiche, a German mathematician and archaeologist, Kosok proposed the figures were markers on the horizon to show where the sun and other celestial bodies rose.