When construction workers began digging the foundation for a new rapid transit bus stop outside of Mexico City in 2019, they happened upon the remains of a stone tunnel from the early 17th century. Replete with rounded archways and long passages, the tunnel features a sluice gate and was part of the Albarradón de Ecatepec, a 2.5-mile-long, colonial-era flood control system built to protect the former Aztec capital—then known as Tenochtitlan—from periodic inundations.
The recently discovered tunnel was constructed in 1605, 80 years after the conquest of the city by Spanish invaders, and contains at least 11 Aztec reliefs and petroglyphs—rock carvings that depict various animals, gods, a temple, and artificial tools. Archaeologists and historians have not yet determined exactly how the petroglyphs made it into the masonry of the Spanish infrastructure project, though it is likely that Indigenous workers contributed much of the construction labor and inserted the temple as an homage to the Aztec rain god Tlaloc. It is also possible, according to ArtNet, that the fragments were taken from a previously demolished Aztec building.
Mexico’s National Institute of Anthropology and History (INAH), which has been working to recover and preserve the entire Albarradón de Ecatepec since 2004, initially intended to convert the tunnel into an archaeological tourist attraction. The petroglyphs were to be moved to an area community center and replaced with on-site replicas for the viewing public. But with the COVID-19 pandemic continuing to upend daily life and national economies, the Mexican government has instead decided to prioritize healthcare costs and other needs over the tunnel project.
Funding shortfalls have prompted authorities with the INAH to re-bury the newly excavated tunnel until the site can be properly preserved and an exhibit can be built. Crews will install masonry around each of the petroglyphs to protect them before temporarily filling the tunnels with dirt, though it is unclear when, or if, the project will eventually proceed.