Archaeologists have discovered a network of tunnels they believe served as the gateway to the Zapotec underworld in the ancient city of Mitla, present-day Oaxaca.

Using a mix of non-invasive ground-penetrating radar, electrical resistivity tomography and seismic noise tomography, joint researchers from Mexico’s National Institute of Anthropology and History, the National Autonomous University of Mexico and the Association for Archaeological Research were able to generate images of the tunnels, which flow beneath the Church of San Pablo. Spanish missionaries later constructed a Catholic church on the site in the 15th century.

The ARX Project Lyobaa team announced its findings in a press conference on 12 May 2023, confirming the existence of the tunnels and chambers.

The Zapotec people (contemporaries of the Aztecs) constructed the structures around 600 BCE as the entrance to the Lyobaa or ‘House of the Dead’. Dominican priest Francisco de Burgoa wrote about the underground Lyobaa temple complex in 1674, shortly before missionaries sealed it off to disconnect the Zapotec people from their ‘pagan’ gods and convert the population to Christianity.

Local legend said that San Pablo’s church was built directly atop the site, and now 3D models have revealed that this blocked-up entrance is located directly beneath the main altar of the Catholic church.

With the rediscovery of the tunnels, researchers hope to ‘determine the true extent’ of the complex and learn more about the Zapotec’s death customs. A second season of non-invasive scans is planned for September 2023 by the ARX Project research team, focusing on the structures to the west and south of the church grounds.

Find out more about Project Lyobaa and see the full report.

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