An international research team is preparing to peer inside one of the Maya civilization's most iconic structures using cutting-edge technology borrowed from particle physics. The team will deploy muography - a non-invasive imaging technique that harnesses cosmic rays - to search for hidden chambers within El Castillo pyramid at Chichén Itzá, Mexico. The groundbreaking study could finally answer long-standing questions about whether secret rooms or even royal burial sites lie concealed within the ancient monument's limestone walls.
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Probing Ancient Secrets Without Disturbing Sacred Stones
The pyramid, also known as the Temple of Kukulcan, was constructed between the 8th and 12th centuries AD in honor of the Yucatec Maya Feathered Serpent deity. According to Mexico's National Institute of Anthropology and History (INAH), researchers will first test the muography technology by attempting to identify two known interior chambers that were discovered during excavations in the 1930s. Successfully detecting these spaces will validate whether the technique can then be applied to the entire structure to search for previously unknown rooms. The study represents a collaboration between INAH, various departments of the National Autonomous University of Mexico (UNAM), Chicago State University, Dominican University, Virginia University, and the Fermi National Laboratory Heritage Daily.
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Two twin muon detectors will be installed in the north and south tunnels of the pyramid. (NAUM Project/INAH)
Revolutionary Technology Borrowed from Particle Physics
Muography uses naturally occurring cosmic-ray muons - subatomic particles that constantly rain down on Earth from space - to reveal the internal density of large structures without drilling, excavating, or causing any damage. The technique has already proven successful in archaeology, having been used to discover hidden chambers in Egypt's Great Pyramid and other ancient monuments. These muons pass through solid matter but are absorbed at different rates depending on density, creating a kind of X-ray image that can reveal hollow spaces, corridors, and chambers inside massive stone structures.
The technology is particularly valuable for studying UNESCO World Heritage sites like Chichén Itzá, where destructive archaeological methods are inappropriate and often prohibited. By positioning sensitive muon detectors around the pyramid, researchers can capture the particles passing through from various angles, building up a three-dimensional map of the monument's interior architecture.
Mexican and American scientists will collaborate to install two muon detectors in the tunnels inside the pre-Hispanic pyramid. (NAUM Project/INAH)
Searching for Royal Tombs Above a Sacred Underworld
Previous studies conducted in 2018 using electrical resistivity imaging (ERI) determined that El Castillo was built directly over a massive water-filled cenote—a natural limestone sinkhole extending approximately 70 feet deep. For the ancient Maya, cenotes were far more than water sources. They regarded these underground chambers as sacred portals to Xibalba, the underworld, and believed they were dwelling places of Chaac, the rain god. The pyramid's deliberate construction above this portal may have held profound religious significance.
The Offerings and Sacrifices rooms, which stand out for the presence of sculptures of a Chac Mool and a jaguar painted red, were discovered. (INAH)
Beyond confirming the known features, the muography project could help evaluate long-standing archaeological theories, including the possibility that an earlier substructure within El Castillo served as a royal burial site. Archaeologists already know that El Castillo contains at least two earlier pyramid structures nested inside, a common practice in Mesoamerican architecture. If successful, this study would mark a significant advance in the non-invasive exploration of Mesoamerican monumental architecture and could revolutionize how researchers investigate similar structures throughout Central America.
Top image: The El Castillo Pyramid at Chichen Itza, Mexico. Source: NAUM Project/INAH
By Gary Manners
References
Heritage Daily. 2025. Study searches for hidden chambers in the El Castillo pyramid. Available at: https://www.heritagedaily.com/2025/12/study-searchers-for-hidden-chambers-in-the-el-castillo-pyramid/156620
INAH. 2025. Researchers are preparing muography to detect interior structures in El Castillo at Chichen Itza. Available at: https://www.inah.gob.mx/boletines/alistan-muografia-para-detectar-estructuras-interiores-en-el-castillo-de-chichen-itza
