High in the Peruvian Andes, a serrated stripe of pits cuts across a barren hillside, so regular and extensive that early pilots mistook it for something almost mechanical. For decades, the “Band of Holes” defied explanation, its roughly 5,200 cavities inspiring theories that ranged from military defenses to alien runways. Now a wave of new research argues that these mystery hollows were neither ritual altars nor messages to the sky, but the working infrastructure of an Indigenous marketplace and accounting system.
Archaeologists say the long line of pits in Peru’s Pisco Valley was used to store and tally goods moving through a regional hub, effectively turning the landscape itself into a giant ledger for local communities and, eventually, the Inca Empire. The solution reframes one of South America’s strangest archaeological puzzles as evidence of sophisticated economic management rather than supernatural spectacle.
The strange geometry of Peru’s Band of Holes
The feature known as the Band of Holes runs along a ridge above the Pisco Valley, a dry corridor that connects coastal Peru with the highlands and the wider Peruvian Andes. From the air, the formation appears as a dotted ribbon, with thousands of human-carved pits marching in rows up and over the terrain, a pattern that early explorers captured in photographs and that modern visitors can locate through detailed mapping of the site. The regularity of the depressions, each roughly similar in size but not identical, suggested deliberate planning rather than random quarrying or erosion.
For more than a century, the formation’s purpose remained opaque, even as archaeologists confirmed that the pits were man-made and likely pre-Hispanic. Local people and visiting researchers counted roughly 5,000 to 5,200 cavities, enough to stretch for more than a kilometer along the slope, and the sheer labor involved hinted at a function important enough to mobilize entire communities. As later studies would show, the Band of Holes sits near a network of ancient roads and overlooks fertile valleys, a placement that would prove crucial to understanding why anyone would carve so many hollows into otherwise unremarkable rock.
From alien runways to accounting: how theories evolved
Before the current consensus emerged, the Band of Holes attracted a catalog of speculative explanations that said more about modern imaginations than about Andean history. Some writers proposed that the line of pits was a defensive trench system, others that it served as a ceremonial procession route, and a few leaned into the sensational, suggesting it might be part of “runways for extraterrestrials” or a coded message visible only from the sky. The lack of artifacts in most of the pits and the difficulty of dating bare depressions in stone left room for such ideas to circulate.
Archaeologists working in Peru gradually pushed back against these narratives, arguing that the feature needed to be read in context with nearby settlements, fields, and roads. Recent work highlighted by Archaeologists has instead tied the site to economic activity, suggesting that the pits were used to organize and record goods in a structured way. That shift, from cosmic speculation to grounded social history, reflects a broader trend in Andean archaeology toward seeing monumental features as tools of governance and exchange rather than purely ritual creations.
A massive marketplace carved into the mountain
The most striking new interpretation casts the Band of Holes as a sprawling open-air market where people from different ecological zones met to trade. Researchers argue that the roughly 5,200 cavities functioned as individual storage cells, each holding sacks or baskets of produce, textiles, or other commodities awaiting exchange. In this view, the hillside became a kind of three-dimensional grid, allowing officials or community leaders to see at a glance how much maize, quinoa, or dried fish had arrived from each group, and to redistribute those goods across the region. One study explicitly describes the feature as a Marketplace and Giant Ledger for the Inca Empire, emphasizing both its commercial and administrative roles.
Soil samples taken from the pits support this market hypothesis. Analyses of microscopic remains recovered from the hollows revealed traces of ancient crops, including poll grains from maize, a staple that underpinned Andean economies and state obligations. These Analyses of soil from the holes indicate that foodstuffs were once stored or processed there, even if later erosion and reuse have stripped away most visible artifacts. Combined with the site’s position overlooking routes that linked coast and highlands, the evidence points to a bustling node where farmers, herders, and traders converged to swap goods in a controlled environment.
The Band of Holes as a living ledger
Beyond serving as a marketplace, the Band of Holes appears to have functioned as a physical accounting system that prefigured or complemented more portable record keeping. A team associated with the University of South Florida has argued that the arrangement of pits mirrors the logic of Andean tally devices, suggesting that officials used the rows and clusters to track obligations and deliveries. Their Research frames the site as a place where quantities of goods were counted and verified, then moved onward through a system of exchange centuries before Europeans arrived.
Drone surveys have strengthened that argument by revealing patterns invisible from the ground. High-resolution mapping shows that the Band of Holes is not a random scatter but a carefully organized sequence of rows that sometimes split, merge, or change size, a layout that resembles at least one known Inca khipu, the knotted-string devices used for numerical records. Investigators who conducted this work reported that They found the arrangement of the Band of Holes similar to an Inca accounting pattern, and also noted its proximity to a network of pre-Hispanic roads that would have funneled caravans of llamas and porters through the area. In effect, the mountain itself became a ledger page, with each pit representing a unit in a larger numerical system.
Dating the pits and tying them to empire
Pinning down when the Band of Holes was in use has been challenging, but radiocarbon evidence from nearby materials now places its active phase in the 14th century. That timing falls within the Late Intermediate Period, when regional powers like the Chincha were flourishing along the coast and before the Inca fully consolidated control. A recent synthesis notes that Radiocarbon dating situates the site in this era, suggesting that local groups first developed the system and that the Inca later adopted or integrated it into their imperial administration.
Other reports echo this sequence, describing how the Band of Holes likely began as a regional innovation and then became part of a broader imperial network of storage and taxation. One overview of the project explains that Peru used the Pisco Valley as a corridor where goods and people moved under an increasingly centralized system under the Inca Empire. Another account notes that the site lies in the heart of Peru Pisco Valley, where a series of around 5,200 pits first drew media attention in the 1930s and have since been confirmed as human-made. Together, these findings place the Band of Holes within a dynamic political landscape, where local ingenuity and imperial oversight intersected on a stony ridge.
How many holes, and what they reveal about Andean math
Even the basic question of how many pits exist has become part of the story, because the counts hint at how ancient administrators thought about numbers. Some surveys describe “more than 5,000” cavities, a figure repeated in a summary that calls Peru’s Band of Holes a vast line of more than 5,000 human-carved pits. Other research rounds the figure to 5,000, as in a study titled Why Did Ancient Peruvians Dig 5,000 Holes Into the Hills, which emphasizes how the layout may reflect hierarchical decimal taxation systems. Still others, focusing on the most complete stretches, specify exactly 5,200 pits, a number that aligns neatly with the base-10 counting favored in Inca administration.
That numerical precision matters because it dovetails with the idea that the Band of Holes was designed for counting. A report on the site notes that Scientists studying the 5,200 m long line of pits in the Peruvian Andes see it as a Massive accounting surface, where each cavity could represent a standardized unit of goods contributed by local groups. Another analysis from the same research network, framed as a New study suggests accounting, underscores that the pattern of pits follows the logic of Andean decimal organization, where groups of ten, one hundred, or one thousand households were taxed and tallied in structured ways.
Rewriting the story of Andean innovation
Seeing the Band of Holes as a market and ledger rather than a mystery monument changes how I understand Indigenous innovation in the Andes. Instead of a curiosity carved for unknown gods or distant visitors, the 5,200 pits become evidence of local people solving practical problems of storage, taxation, and fairness in a complex landscape. One synthesis of the project, produced with the University of South Florida, explicitly contrasts the sober reality of accounting with the earlier fascination for the sensational, arguing that the true story is more impressive than any alien runway.
For me, the most compelling aspect of the new research is how it ties a single enigmatic site into a broader web of Andean knowledge. The Band of Holes now sits alongside khipu cords, state storehouses, and road networks as part of a coherent system of governance that stretched from coastal valleys to high mountain passes. A recent overview of the work on Mysterious Holes in Peru May Have Served as a Marketplace and Giant Ledger for the Inca Empire captures that shift in perspective, showing how a once-baffling pattern of pits now reads as a testament to Indigenous economic intelligence. The mystery has not vanished so much as matured, revealing a past in which numbers, not myths, ruled the mountain.
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