In the spring of the year 2017, two divers swam through a small passageway under the Yucatán peninsula. They had swum nearly half a mile through the Mexican cave system, when they came upon a chamber.

The threshold, which spanned more than 28 inches across, offers an extraordinary insight into the life and behavior of some of the first residents of the Americas.

In the room above the small passage was an ancient scene: an 11,000-year-old red ocher pigment extraction site. The mine is among the few geological locations that detail how ancient civilizations extracted pigments to use in sacred rituals and cave painting.

The report, which was published in Science Advances, provided a remarkable insight into the life of several of America's first settlers. The ancient people lived in Yucatan thousands of years well before the ancient Maya civilization existed.

Newly Discovered Chamber

The exploration of the mine began when students in a cave surveying class discovered another tunnel in the cave system. The researchers immediately swam through the narrow tunnels, leading to the discovery of the site.

The chamber floor had pits. The stalagmites and stalactites were also scattered with archaeologists believing that they were used as makeshift hammers. The team also found burnt rock and charcoal remains from fires that may have once lit the darkness of the cavern.

Some researchers claimed that the mines might have been a site, where the ancient people held sacred rituals.

Experts said the Mayan civilization linked cave entrances to the underworld as well as a source of sacred water. The ocher that was found inside the system was also a vital part of the rituals for the Mayans and the Aztecs.

First Inhabitants

In 2014, a group of archaeologists found a complete skeleton submerged underwater in a different chamber of the cave system.

The skeleton, named "Naia," belonged to a teenager who presumably fell in a cavity near the mine around 13,000 years ago. The discovery led researchers to believe she was one of the earliest inhabitants of the Americas.

According to the team of archaeologists, Naia had a narrow face. Her eyes were wide-set and her forehead low and prominent. She had a low and flat nose, with her teeth projecting outward.

Her features and the genetic markers found indicated she shared a common lineage with the Native Americans of today.

The girl's skeleton was found in a pile of bones at the bottom of the chamber. The suite of bones included those from saber-toothed cats, ground sloths, and other animals.

Naia was found with a broken pelvis that was likely the result of the fall. She also suffered from tooth decay and osteoporosis, a sign she may have become pregnant at an early age.

In the enclosed cave system under Quintana Roo, researchers also found at least nine more ancient people. Their remains were perfectly preserved after the rising seas some 8,000 years ago filled the caves.

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