Sediment analysis and drone photography of the iconic South American monument of Monte Sierpe (aka «Band of Holes») support a new interpretation of this mysterious landscape feature as part of an Indigenous system of accounting and exchange.
Sediment analysis and drone photography of the iconic South American monument of Monte Sierpe (aka «Band of Holes») support a new interpretation of this mysterious landscape feature as part of an Indigenous system of accounting and exchange.
Stretching 1.5 km across the Pisco Valley of the southern Peruvian Andes, Monte Sierpe (meaning serpent mountain) is a large row of approximately 5,200 precisely aligned holes (1–2 m wide and 0.5–1 m deep), organized into sections or blocks.
It first gained modern attention in 1933, when aerial photographs of the holes were published in National Geographic, but the monument’s purpose is still uncertain.
«Hypotheses regarding Monte Sierpe’s purpose range from defense, storage, and accounting to water collection, fog capture, and gardening», says lead author Dr. Jacob Bongers from the University of Sydney. «The function of the site remains unclear.»
To shed new light on this ambiguous feature of Peru’s ancient landscape, an international team combined microbotanical analysis of sediment samples from the holes with high-resolution aerial imagery, presenting new insights into Monte Sierpe’s organization and use at both micro and macro scales. Their results are published in the journal Antiquity.
According to the authors, their most important finding is the microbotanical evidence, which uncovered plant remains in the holes including crops such as maize and wild plants that are traditionally used for making baskets.
«These data support the hypothesis that during pre-Hispanic times, local groups periodically lined the holes with plant materials and deposited goods inside them, using woven baskets and/or bundles for transport», explains Dr. Bongers.
Perhaps most intriguing, however, is the aerial imagery, which indicates numerical patterns in the layout of the holes. Combined with the monument’s segmented organization, Monte Sierpe mirrors khipus: Inca counting devices made from knotted string.
This could indicate that Monte Sierpe constituted a monumental system of accounting during the Inca period, administered by the Inca state for the collection of tributes.
Importantly, Monte Sierpe is strategically located between two Inca administrative sites and near the intersection of a network of pre-Hispanic roads. It is positioned in a transitional ecological zone (chaupiyunga) between the highlands and lower coastal plain, a space where groups from both regions would have met and exchanged goods.
Combined with the microbotanical and aerial findings, this suggests that Monte Sierpe was initially constructed and used by the pre-Inca Chincha Kingdom for regulated barter and exchange, later developing into an accounting place under Inca rule.
«This study contributes an important Andean case study on how past communities modified past landscapes to bring people together and promote interaction», Dr. Bongers concludes. «Our findings expand our understanding of barter marketplaces and the origins and diversity of Indigenous accounting practices within and beyond the ancient Andes.»

GM is taking the unprecedented step of removing some of the badging on its unsold trucks starting in 2026. Here’s how GM ended up in this weird situation.
Allison transmissions have been a valued component used in General Motors’ heavy-duty trucks since 2001. What is not generally well-known is that GM was the owner of Allison for a period that started in 1928 and ended in 2007, when Allison was purchased by the Onex Corporation and the Carlyle Group, a global private equity firm. Allison was also connected to Detroit Diesel during a part of its history.
As of June 29, 2026, which represents the end of the 180-day sell-down period that follows the December 31, 2025, conclusion of GM’s branding agreement with Allison, no Allison badging will be permitted on any Chevrolet or GMC heavy-duty trucks remaining in inventory. This means that any Allison transmission-equipped trucks must have their Allison badges removed. GM has stated that it will «initiate a field action to retrofit any remaining Allison-badged inventory with a non-Allison badge.»
There is some major irony to this move by GM, due to the fact that there have not been any Allison transmissions in GM’s heavy-duty trucks, the trucks that are affected by this action, since 2020. That is when GM replaced Allison transmissions in those vehicles with its own 10-speed automatic that it had co-developed with Ford. Since 2020, GM has marketed that 10-speed automatic as ‘Allison-branded’ (like the one paired to the 2025 6.6L Duramax diesel in several vehicles), which according to TFL Truck, the original source, meant that Allison simply validated GM’s design. Nothing more. Yet, as highly regarded as they seem to be, based on this co-branding exercise, Allison transmissions are not perfect, according to their owners. What else should you know about GM removing Allison badging from unsold trucks?
Putting this issue into perspective, it is highly likely that GM saw the continuation of this co-branding agreement as a needless waste of money. This is particularly true when you consider that there have not been any actual Allison transmissions used in GM trucks for the past six years.
And remember, when this exercise started back in 2001, GM still owned Allison, so any money spent on co-branding helped another member of the GM family, with any costs simply going out of one GM pocket and into another. With Allison under external ownership, that is no longer the case. According to Shad Balch, Chevrolet Communications Director, «.after months of going back-and-forth we could not agree on terms to extend the agreement.» So it apparently did come down to the money.
Another side of this has to do with the difficult conditions being experienced by American automakers at the present moment. Between tariff and trade problems, supply chain issues, inflation, and the collapse of the EV market after the tax credits were removed, there is no more room for wasteful or unnecessary spending. On top of that, GM may have simply come to the conclusion that heavy-duty pickup truck buyers no longer need to be reassured by a brand name that their transmission can handle the extreme torque of a diesel engine.