By Paula Neely
In 2007, in a jungle north of the city and Maya Center of Tulum in Quintana Roo, Mexico, a team of cave divers entered a sinkhole, or cenote, and began exploring a pitch-black tunnel that had been flooded from floor to ceiling by rising sea levels after the last Ice Age. As they laid a line to mark their route, their flashlights illuminated stalactites and stalagmites on the ceiling and floor. But when they reached the end of the passageway about half a mile from the entrance, there was nothing beyond it but a watery black pit that swallowed up their lights.
“There was no reflection of light off the walls — just darkness,” said diver Alejandro Álvarez. He and the other divers, Alberto Nava Blank and Franco Attolini, explored as much of the pit as they could, but it was so deep, they couldn’t safely dive to the bottom with the air tanks they were using. They named it Hoyo Negro, which means “black hole” in Spanish.
A few weeks later the crew returned with equipment that would allow them to dive deeper. When they reached the bottom of the chamber, they almost immediately saw the skeletal remains of an ancient elephant, known as a gomphothere, that went extinct about 12,000 years ago. They also saw the perfect skull of a human — upside down with teeth intact — right next to the gomphothere. “It was incredible to see,” said Nava Blank. The group continued exploring the boulder-strewn floor and saw an array of large bones “all over the place,” Álvarez said.
The chamber, which measures about 200 feet wide and roughly 150 to 200 feet deep, is part of Outland Cave, one of many complex underground cave systems in the Yucatán Peninsula that became submerged after the last Ice Age, creating ideal conditions for preserving Late Pleistocene fossils. Among the cave sites in the Mexican state of Quintana Roo on the eastern coast of the Yucatán Peninsula, Hoyo Negro is the most spectacular, according to Helena Barba-Meinecke, head of underwater archaeology in the Yucatán for Mexico’s National Institute of Anthropology and History (INAH).