A ritual cave has been discovered beneath the ancient Maya city of Chichen Itza. Archaeologists found more than 150 objects relating to ritual practices in the cave, which they said had been untouched for more than 1,000 years.

The expedition, which was partly funded by a grant from the National Geographic Society, was led by Nat Geo explorer Guillermo de Anda and a team from the Great Maya Aquiver Project. De Anda came across the cave while looking for a sacred well beneath the city on Mexico’s Yucatán Peninsula.

“I couldn’t speak, I started to cry,” he told National Geographic. “I’ve analyzed human remains in [Chichen Itza’s] Sacred Cenote, but nothing compares to the sensation I had entering, alone, for the first time in that cave. You almost feel the presence of the Maya who deposited these things in there.”

The cave system, called Balamku (“Cave of the Jaguar God”) was found by farmers in 1966 and visited by archaeologist Víctor Segovia Pinto. At the time he said there were archaeological artifacts down there. However, instead of exploring further, he ordered the farmers to seal up the cave—and it remained that way until last year.

Ritual objects, including vases, incense burners and decorated plates, were found in a series of cave chambers. Researchers believe these objects will provide vital clues about the rise and fall of the city—and indeed the civilization itself. In total, 155 artifacts have so far been identified. One was found to have the face of the rain god Tlaloc, while another had markings representing the Maya universe—the symbolic ceiba tree.

Balamku is far larger than another nearby ritual site discovered in 1959. This cave, called Balankanche, contained 70 objects. “Balamku appears to be the ‘mother’ of Balankanche,” De Anda told the magazine. “I don’t want to say that quantity is more important than information, but when you see that there are many, many offerings in a cave that is also much more difficult to access, this tells us something.”

National Geographic Explorer Guillermo de Anda examines a cache of ritual vessels inside the Balamku (Jaguar God) cave in Yucatán, Mexico. The objects have been untouched for at least 1,000 years.KARLA ORTEGA

The Maya civilization existed between 2,000 BCE and the 1600s, with the arrival of European conquests. It had started to decline hundreds of years earlier, however. During the eighth or ninth century, there was a collapse and cities started to be abandoned.

Chichen Itza was one of the biggest and most diverse of the Maya cities, peaking between the ninth and 13th centuries. According to UNESCO, there were no major monuments built after the 13th century, and it rapidly declined around 1440 AD. Shortly after, it was abandoned. Researchers have previously speculated this could have been the result of droughts, conquests and exhausted soils.

The latest discoveries in the cave should provide clues about the timeline of events that led to the city being deserted. “Balamku can tell us not only the moment of collapse of Chichen Itza,” De Anda said. “It can also probably tell us the moment of its beginning. Now, we have a sealed context, with a great quantity of information, including usable organic matter, that we can use to understand the development of Chichén Itzá.”