In 1609, a mestizo historian named Garcilaso de la Vega sat down in Córdoba, Spain, and wrote about the tunnels he’d entered as a boy in Cusco. He described underground streets — actual avenues — stretching from the hilltop fortress of Sacsayhuamán to the Coricancha, the Temple of the Sun, nearly two kilometers away. He recalled the darkness, the disorientation, and a rule every local knew: you do not go in without a rope tied to the entrance door, unwound as you walk, because the labyrinth swallows people. He never ventured beyond where sunlight reached. He was, by his own account, too afraid.

Four centuries later, in January 2025, a team of Peruvian archaeologists announced they had confirmed exactly what Garcilaso described: a 1,750-meter underground passage connecting Sacsayhuamán to the Coricancha, buried beneath the streets of modern Cusco. The tunnels are real. But who built them — and when — remains a question that nobody has fully answered, and that the Inca themselves may not have been able to answer either.

The Chinkanas: A Labyrinth by Name

The Quechua word chinkana means “place where one gets lost.” It is not a reassuring name for a tunnel system. The term has been applied to a network of underground passages beneath Cusco for as long as anyone has been writing about them, and the name predates the writing.

Two surface access points have been known for centuries. The Chinkana Grande, in the upper sector near Sacsayhuamán, was sealed — reportedly dynamited — by soldiers in 1927, then sealed again with mud by the Cusco municipality in the 1990s. The Chinkana Chica, a smaller, naturally formed passage with Inca carvings on its walls, remains partially accessible, with about fifteen meters of visible corridor before darkness takes over. A serpent-shaped carved stone marks the entrance — a symbol of Ukhu Pacha, the Andean underworld, the realm beneath the earth where different rules apply.

The passages themselves, based on the 2025 survey led by archaeologists Jorge Calero Flores and Mildred Fernandez Palomino, are approximately 2.6 meters wide and 1.6 meters tall. That’s wide enough, the colonial chroniclers noted, for an Inca ruler to be carried through on a litter. The total gallery network may exceed eight kilometers. Forty-five days of ground-penetrating radar work, acoustic prospecting, and archival research produced the confirmation. The team believes they located the true entrance to the main underground thoroughfare.

But Calero Flores and Fernandez Palomino were not working from a blank slate. They were following a trail of documentation stretching back to the late sixteenth century — and a trail of bodies.

The Dead, the Mad, and the Golden Bars

The chinkanas have a body count.

In 1624, three men — Francisco Rueda, Juan Hinojosa, and Antonio Orue — entered the main passage at Sacsayhuamán searching for its secrets. They were never seen again. The event lodged itself in Cusco’s collective memory as a cautionary tale, the kind of story parents tell children about places they should not go.

William Montgomery McGovern, the American explorer, recorded a stranger account in his 1927 book Jungle Paths and Inca Ruins: a man who allegedly emerged from the tunnels at the Temple of the Sun carrying two golden bars, his mind destroyed by days of underground wandering. He died shortly after surfacing. The gold was real. The man was not recoverable.

The American traveler Ephraim George Squier, writing in 1867, documented what finally prompted official action. General San Roman, serving as Prefect of Cusco around 1841, ordered the tunnel entrances walled up after three boys entered and never came out. They starved to death somewhere in the labyrinth’s recesses. San Roman decided that whatever was down there was not worth more dead children.

The pattern is consistent across centuries: people go in, people don’t come out, authorities seal the entrances, and a generation later someone opens them again.

What the Chroniclers Wrote

The colonial-era documentation of the chinkanas is unusually rich for something that was, officially, supposed to be sealed and forgotten.

Fray Martín de Morúa wrote about the tunnel network around 1590, making him the earliest known chronicler to describe it in writing. An anonymous Jesuit text, published in the General History of the Jesuits around 1600, provides the most detailed early account: a tunnel beginning at the Temple of the Sun, running beneath what was by then the bishop’s housing behind Cusco’s Cathedral, and terminating at Sacsayhuamán. The Jesuit chronicle states that successive Inca dynasties spent decades draining subterranean aquifers feeding the Huatanay River in order to excavate the passageways. In wartime, the system allowed rulers besieged at Sacsayhuamán to descend underground and emerge, undetected, at the Coricancha.

Garcilaso de la Vega, whose personal childhood memories give his 1609 Comentarios Reales de los Incas an unusual texture, described not just the tunnels but the social knowledge surrounding them. Everyone in Cusco knew the tunnels existed. Everyone knew not to go in without a guide rope. The labyrinth was common knowledge and common fear simultaneously.

Then there are the treasure hunters. In 2010, historian Ronald Camala Valenzuela discovered a notarial document from 1642-1643 in Cusco’s Royal Archive. It details Dominican friars authorizing a Master Alonso Fernandez de Velasco to search the chinkana for Inca treasure. The Spanish understood the tunnels as vaults — places the Inca had hidden their gold before the conquest. Whether they found anything is unrecorded.

The Question of Age

Here is where the story gets genuinely complicated.

The colonial chroniclers describe the chinkanas as Inca constructions — monumental engineering projects undertaken by specific rulers. The anonymous Jesuit attributes their excavation to multiple Inca dynasties working in sequence. Cieza de León recorded that the ruler Pachacuti commanded 20,000 laborers from the provinces to build Sacsayhuamán, and the tunnels are generally treated as part of that same imperial construction program.

But Sacsayhuamán was not built on empty ground.

Carbon-14 dating confirms that the Killke culture constructed structures at the site around 1100 CE — at least a century before the Inca arrived. The Killke occupied Sacsayhuamán from roughly 900 to 1200 CE. Excavations in 2007 and 2008 uncovered a Killke temple on the fortress’s edge, along with irrigation systems and a roadway. These finds reframed Sacsayhuamán: it was not purely a military fortification, as long assumed, but a sacred ceremonial site that the Inca inherited and expanded.

Did the Killke dig tunnels? Some geological studies suggest that portions of the tunnel network at Sacsayhuamán were created by natural erosion and subsequently modified by human hands. If that’s the case, the question is not who built the tunnels but who found them first, who shaped them, and who expanded them into something functional. The Inca may have been the last in a sequence of cultures to use a subterranean network that was already ancient when they arrived.

This remains, as researchers have acknowledged, insufficiently studied. The 2025 survey confirmed the tunnels’ existence and dimensions. It did not establish a definitive construction date.

Chavín de Huántar: Proof That Pre-Inca Cultures Built Underground

If there is any doubt that civilizations before the Inca were capable of sophisticated underground construction, Chavín de Huántar demolishes it.

Located in the Ancash highlands, the Chavín temple complex dates to approximately 1200–200 BCE — over two thousand years before the Inca Empire existed. Stanford archaeologist John Rick, who has directed excavations at the site for years, has documented at least 36 interconnecting underground tunnels and passageways beneath the temple complex. In May 2022, Rick physically crawled through a 40-centimeter-diameter duct into a hidden gallery that had been sealed for approximately three millennia.

What he found inside was remarkable. The gallery — dubbed the Condor Gallery — contained two ceremonial stone bowls, one featuring a three-dimensional Andean condor sculpted in stone, weighing 17 kilograms. These were votive offerings, deposited when the gallery was sealed around 1000 BCE. The gallery itself is now considered the oldest known structure at Chavín de Huántar.

The underground architecture at Chavín was not utilitarian. It was theatrical. Researcher Miriam Kolar studied the acoustic properties of the stone galleries and found that sounds within them are difficult to localize, producing disorienting reverberations. Small holes in chamber walls allowed priests to whisper incantations or blow pututu — conch shell trumpets — filling the underground spaces with sound that seemed to come from everywhere and nowhere. Combined with strong evidence for ritual use of San Pedro cactus, a psychoactive plant native to the Andes with over two thousand years of documented ceremonial use, the tunnels at Chavín appear to have been designed as instruments of sensory manipulation. You walked underground, you lost your sense of direction, the walls spoke to you, and you were not sober.

The point is this: a culture that predated the Inca by two millennia built an underground labyrinth of extraordinary sophistication. The engineering knowledge existed in the Andes long before Pachacuti commanded his 20,000 laborers. The question is not whether pre-Inca tunnel construction was possible. It demonstrably was.

The Wari Connection

Between Chavín and the Inca, the Wari Empire (roughly 600–1000 CE) controlled much of the Peruvian highlands, including territory around Cusco. At Pikillacta, a major Wari administrative center southeast of Cusco founded around 650 CE, archaeologists have documented an elaborate underground sewage system — evidence that the Wari were comfortable building beneath the surface.

The Wari also occupied sites later claimed by the Inca, including areas near Cusco itself. When the Inca expanded in the thirteenth century, they were moving into landscapes already shaped by centuries of Wari and Killke habitation. The notion that the Inca found existing infrastructure — above and below ground — and incorporated it into their own building programs is not speculative. It is the standard model for how Andean civilizations operated.

Pi Rambla and the Sealed Door

One episode in the modern history of the chinkanas deserves particular attention. In 1982, Spanish explorer Anselm Pi Rambla visited the Prior of the Convent of Santo Domingo — the church built directly on top of the razed Coricancha — and was told that the chinkana entrance beneath the church was known but had been sealed since the devastating 1950 earthquake, when the passage was blocked to reinforce the church’s foundations.

Between 2000 and 2003, Pi Rambla ran Project Koricancha with permits from the Peruvian government. His team used ground-penetrating radar and physical excavation. They accessed colonial-era crypts beneath Santo Domingo’s main altar through a wooden trapdoor. Behind a sealed brick wall — seventeenth-century colonial masonry — Pi Rambla described finding what he called “a huge Inca construction tunnel,” its walls lined with rectangular andesite stones, expertly carved and fitted with tightly joined seams. The ceilings were smooth slabs, approximately two meters long, fitted together with the precision that characterizes Inca stonework at its best.

The project ended before the team could fully enter the tunnel. The Dominican order complained that excavations were endangering the church structure. The permits were not renewed.

This is the recurring pattern with the chinkanas: approach, partial confirmation, institutional resistance, withdrawal. The tunnels are acknowledged, then resealed. Confirmed, then left unexplored. The 2025 survey broke this pattern somewhat — the findings were announced publicly, covered by Smithsonian Magazine, Archaeology Magazine, Heritage Daily, and others. But physical entry into the main passage system has still not occurred.

What Remains Underground

The confirmed facts are these: a tunnel network of at least 1,750 meters connects Sacsayhuamán and the Coricancha beneath Cusco. The total system may extend more than eight kilometers. Pre-Inca cultures — the Killke at Sacsayhuamán, the Chavín in Ancash, the Wari across the highlands — all built underground. Sacsayhuamán was occupied for at least two centuries before the Inca claimed it. The Inca themselves, through their chroniclers and the Spanish who recorded their oral traditions, described the tunnels as military infrastructure, escape routes, and passages between sacred sites.

What remains unproven is the age of the Cusco tunnels specifically. Were they Inca imperial projects, as the chroniclers state? Were they Killke constructions that the Inca expanded? Were they natural formations — erosion channels in the limestone — that successive cultures adapted over centuries? The answer may be all three, in different sections.

But there is a deeper question that the archaeological evidence keeps circling without answering. The Inca were exceptional administrators and builders, but they were also, by their own account, inheritors. They absorbed the Killke, occupied Wari sites, and claimed older sacred landscapes as their own. When Garcilaso de la Vega described the chinkanas in 1609, he wrote about them as things that had always been there — part of the fabric of Cusco, as old as memory. He did not describe their construction. He described their existence.

If Calero Flores and Fernandez Palomino’s team eventually enters the main passage — past the serpent mouth, past the sealed entrances, into the kilometers of corridor that radar says are there — what will the stonework tell them? Will it be Inca masonry, with its signature polygonal joints? Or will there be older walls behind it, rougher, belonging to people whose names the Inca themselves may not have known?

The tunnels have been waiting, sealed in darkness, for at least five centuries. They may have been waiting much longer than that.