A Polish-Peruvian archaeology team has mapped more than 2.5 kilometres of Inca-era roads that had lain hidden under rainforest on the slopes of Mount Yanantin, directly across the Urubamba Valley from Machu Picchu. The longest single stretch runs at least 1.2 kilometres. Researchers from the University of Warsaw’s Centre for Andean Studies found the network by flying laser scanners on drones over terrain too dense to survey on foot, during fieldwork carried out in July and August 2026.
Alongside the roads, the team also documented previously unrecorded terraces, platforms and circular structures, evidence that the region opposite the Inca citadel was far more developed than earlier surveys suggested. Professor Mariusz Ziolkowski, who directs the Centre for Andean Studies, is leading the project.
Machu Picchu and its surrounding cultural landscape have carried UNESCO World Heritage status since 1983, and archaeologists have combed the area for more than a century. Even so, the citadel keeps yielding features nobody had mapped, and this year’s fieldwork, announced by the university Ziolkowski leads, adds a road network to a site whose known layout researchers had assumed was largely settled.
Laser pulses reach where machetes cannot
The survey area sits between roughly 2,000 and 2,700 metres above sea level, blanketed in tropical vegetation dense enough that walking a straight line can take hours. To get past that barrier, the team turned to LiDAR, Light Detection and Ranging, mounted on drones. The scanners fire laser pulses at the ground; many bounce off the forest canopy, but enough slip through gaps in the leaves to reach the soil beneath, and researchers can digitally strip away the vegetation afterward to build a three-dimensional model of the terrain hidden underneath it.
Ziolkowski told the Polish Press Agency that one researcher needed around three hours to travel just 250 metres through the forest using a machete, a pace that makes ground surveys of a landscape this size impractical. After the LiDAR data revealed one path already known to locals, the team ran further drone surveys and began uncovering a much larger network of narrow, zigzagging routes threading across the mountainside.
The technique works by measuring how long each laser pulse takes to bounce back to the sensor. Pulses that hit leaves or branches return quickly; the few that slip through gaps in the canopy travel farther before reaching the ground and take longer to return. Software then separates the two signals and discards the vegetation returns, leaving a bare-earth elevation model that would otherwise take years of machete-and-compass fieldwork to approximate.
A network that could double once the analysis catches up
So far the survey has identified more than 2.5 kilometres of previously unknown pre-Columbian roads, with the longest continuous section extending at least 1.2 kilometres. Ziolkowski said the eventual total could run to at least twice that figure, since the team has completed only the first stage of a time-consuming LiDAR analysis.
Whether the Incas themselves built every stretch remains an open question. The zigzagging construction and layout match known Inca engineering, but some sections may predate the Inca period and have been rebuilt or reused later, and researchers say further fieldwork will be needed to pin down when individual segments were constructed.
The far bank of the Urubamba was not empty after all
More than 60 archaeological sites are already documented within Machu Picchu National Park, most of them concentrated on the left bank of the Urubamba River near the main citadel, Llaqta de Machu Picchu. The newly mapped roads sit on the opposite bank, in the Mandor region, which the team is now studying specifically because of how directly it faces the famous site across the valley.
Ziolkowski said the discoveries both complement and significantly revise existing hypotheses about how the wider complex functioned, since they show substantial Inca-era development on a side of the river long treated as peripheral. New observations even raise the possibility that a feature long labeled the defensive “Mandor Wall” may instead incorporate an elevated ceremonial road aligned toward the Yanantin summit, which rises about 4,100 metres.
Poland and Peru plan more digging next season
This year’s fieldwork drew on a team including Dr. Jan Klaput of the University of Warsaw’s Centre for Andean Studies, Dr. Bartlomiej Cmielewski of Wroclaw University of Science and Technology, who supervised the drone-based LiDAR scanning, Dr. Pawel Dabek of Wroclaw University of Environmental and Life Sciences, and Peruvian archaeologist Jeff Rocky Contreras Soto of Apu Space. Dr. Nino del Solar Velarde, head of Machu Picchu Archaeological Research Coordination at the Regional Directorate of Culture in Cusco, supervised the work on the ground, and the University of Warsaw funded the project.
Researchers are now discussing a longer-term program with Peru’s cultural authorities that would extend the LiDAR survey into new areas and seek permission for targeted excavations along some of the newly found routes. The precise coordinates of the roads are being kept confidential for now, to protect the remains from unauthorized visits before archaeologists can document them properly.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
More from Morning Overview
