Beneath a 16th-century convent in eastern Yucatán, Mexico, archaeologists have discovered a remarkable collection of weapons hidden in an underground cenote, or sinkhole. The cache includes an iron cannon on its wooden carriage and more than 150 rifles and muskets that were thrown into the water almost 180 years ago.
Mexican government forces dumped these weapons in the cenote between 1847 and 1848 during the Caste War of Yucatán, a major Maya uprising. They wanted to prevent the weapons from falling into the hands of rebel fighters. The strategy worked. The rifles, made in Spain and England, sank into the fresh water and remained hidden for generations.
Archaeologists from INAH's Underwater Archaeology unit documented the findings in February 2026 using special photography techniques to create detailed three-dimensional models. The team decided to leave the artifacts in place because the cenote's water chemistry protects them better than any museum could.
Cenotes held deep spiritual significance for the Maya people. They were sacred places and sources of fresh water on the Yucatán Peninsula. The Síis Já cenote contains artifacts from many different time periods, including pre-Hispanic pottery and ceramics alongside the 19th-century weapons.
However, archaeologists noticed a concerning sign: the local catfish population has disappeared, suggesting the aquifer feeding the cenote has become contaminated. Experts plan more surveys and will work to remove modern debris left by unauthorized visitors.