A nearly 1,000-year-old collection of cave drawings is secretly embedded within North Alabama’s mountain range along the foothills of lower Appalachia.

While researchers are keeping the cave’s location under wraps, they were willing to detail to academic journal Antiquity the treasure trove that they deem to be the richest prehistoric cave art site on the continent.

Advanced photography allowed the drawings, which appear to show people donned in Native American regalia, to be uncovered through the mud that had accumulated on the cave walls throughout the years.

According to University of Tennessee anthropology professor Jan Simek, the art could depict spirits of the dead.

“They are either people dressed in regalia to look like spirits, or they are spirits,” said Simek. “The term we like to use is that they were ‘materializing’ those spirits through the costumes that they wore.”

While the exact location is known only to the researchers, the cave is situated at the southern end of the Appalachian Plateau. According to NBC, the drawings were carved by Native Americans who lived during the late Woodland culture phase in the region.

Native American tradition maintained that caves were entrances to the underworld, a belief reflected in the unearthed drawings.

Dylan Smith is a staff writer for Yellowhammer News. You can follow him on Twitter @DylanSmithAL