The exact location of the 19th Unnamed Cave, somewhere on private land in northern Alabama, is a closely guarded secret. What’s inside is too precious to risk destruction. An 80-foot-wide, east-facing mouth leads to a long tunnel where the ceiling and floor draw closer and closer together. You can’t quite stand up, but you don’t need to crawl, says photographer Stephen Alvarez, founder of the Ancient Art Archive and co-author of a new paper on the cave. The floors are uneven. Big pools of water are scattered everywhere. When you’re a long way from the entrance but can still see some daylight, that’s where the artwork begins.

Hundreds of images are etched into mud across roughly 4,300 square feet of the cave’s ceiling. Abstract shapes and swirling lines appear alongside rattlesnakes, bears, insects, birds and humanlike figures created by Native American artists under the flickering light of river-cane torches sometime between 660 and 949 C.E. The artwork continues well into the cave’s dark zone, where visitors can only see a hand in front of their face with the assistance of artificial light. Fog sometimes forms in the cave’s cool, damp air; this wet environment helped the artwork survive for more than 1,000 years.

“If the wet clay dried out all the way, it would almost certainly simply blow away, even in the very light air currents that occur underground,” says Jan Simek, an archaeologist at the University of Tennessee, Knoxville.

The 19th Unnamed Cave is the most extensive of all known cave art sites in the Southeastern United States. Simek and his colleagues have been steadily documenting these sites over the past several decades—and, in a new study published today in the journal Antiquity, they report that the 19th boasts even more images than are visible to the naked eye. By creating 3-D scans of the cave, they revealed previously unseen giant figures, including life-size drawings of humans in enigmatic regalia and an 11-foot-long diamondback rattlesnake.

Tens of thousands of Native American rock paintings (known as pictographs) and carvings (petroglyphs) adorn boulders and canyon walls across North America. But archaeologists have only recently identified artworks in the dark zones of the continents’ caves. They now know of about 100 art-filled chambers in the vast limestone cave system of the Southeast. The first site was found in 1979, when cavers spotted an image of a bird while exploring a cave, now dubbed Mud Glyph Cave, in Tennessee. Later, in the mid-1990s, Simek, who was then studying another newly discovered site in Tennessee, put out a message on a caving forum, wondering if users had noticed any similar artwork during their trips underground. Tips started pouring in.

Anthropomorph in regalia from 19th Unnamed Cave, Alabama
Anthropomorph in regalia from 19th Unnamed Cave, Alabama Photograph by S. Alvarez / Illustration by J. Simek

In 1999, Simek published an initial description of the 19th Unnamed Cave with caver and photographer Alan Cressler. Alvarez visited the site with Cressler and Simek but had trouble capturing the artwork on camera because the glyphs were drawn on such a low ceiling.

“I could not make an interesting image of that ceiling,” says Alvarez, whose main client has long been National Geographic magazine. “There would be no way in God’s green Earth a magazine was going to publish one of those pictures.”

By 2017, however, digital technologies had greatly improved. The team returned to the cave to create a 3-D model of the site with photogrammetry, a technique in which thousands of high-resolution photos are stitched together. Finally, the researchers could examine the ceiling as if the cave had no floor. Simek intended to use the models to measure the distances between the glyphs and assess their relationship to each other. But in the 3-D images, new mud glyphs emerged: four human-like figures in intricately patterned clothing (the largest of which measures nearly seven feet in length) and the giant snake, whose pattern suggests it’s a diamondback—an animal sacred to Indigenous groups of the Southeast.

Serpent figure with a round head and diamond-shaped body markings from 19th Unnamed Cave, Alabama. Note that the base of the engraved glyph joins a natural fissure in the ceiling limestone.
Serpent figure with a round head and diamond-shaped body markings from 19th Unnamed Cave, Alabama. Note that the base of the engraved glyph joins a natural fissure in the ceiling limestone. Photograph by S. Alvarez / Illustration by J. Simek

The fact that these drawings were made on such a large scale, and in such a difficult to reach location, suggests a strong degree of intention behind their creation. “It wasn’t doodling,” Simek says. “They had to lay them out, at least in their head, and maybe even a little bit on the wall, in order to be able to draw them the way they did.”

So far, the meaning of the human figures remains elusive. Ethnographic records and initial consultations with descendant Indigenous collaborators have not revealed the identity of these characters, Simek says. But he thinks the artwork likely held some kind of spiritual significance, as the region’s Indigenous groups considered caves portals to the underworld during the so-called Woodland period when the art was created. Descendant groups, such as the Cherokee, attest to that significance as well.

“We’ve been using caves for tens of thousands of years,” says Beau Duke Carroll, an archaeologist with the Eastern Band of Cherokee Indians Tribal Historic Preservation Office. “Studies like these really put a spotlight on that.”

Panorama of the entire ceiling model from the 19th Unnamed Cave, Alabama
Panorama of the entire ceiling model from the 19th Unnamed Cave, Alabama Photograph by Stephen Alvarez

Carroll wasn’t involved in the research on the 19th Unnamed Cave, but he has been working with Simek to study more recent cave markings. In 2019, the pair published a paper on Cherokee inscriptions from 1828 inside Manitou Cave in Alabama. This text, also deep inside the dark zone, documents a ritually important game of stickball. It was written in Cherokee syllabary, a writing system that was only formally adopted by the tribe a few years prior. Since that study’s release, Carroll has continued looking for inscriptions written in Cherokee syllabary in the region’s caves—and he says he’s finding them in more places than he’d expected to.

“It’s important to stress that the archaeology we’re talking about here is part of a continuum that is still with us,” Simek says. “It’s not just history. The descendants of these people are still alive, still with us. The cultures are still with us. They’re vibrant and living.”

Smaller mud glyphs from 19th Unnamed Cave: a) coiled serpent figure with head in the center, b) wasp with head to the left and abdomen to the right, c) stylized bird and d) anthropomorphic figure surrounded by swirling lines
Smaller mud glyphs from 19th Unnamed Cave: a) coiled serpent figure with head in the center, b) wasp with head to the left and abdomen to the right, c) stylized bird and d) anthropomorphic figure surrounded by swirling lines Alan Cressler

Alvarez hopes to capture that immediacy and vibrancy by better documenting rock art sites with his Ancient Art Archive project. “If you just looked at where I live, and what I eat, and who I buy things from, that’s a pretty limited view into my interior world,” he says. Artwork, however, offers a very different window into the lives of others. Alvarez has been applying the technology used in this study to craft virtual reality experiences that give the public access to otherwise inaccessible sites, like the Paleolithic Chauvet Cave in France.

“You really can’t divorce rock art and cave art from its surroundings,” he says. “Artists who made places like the 19th Unnamed Cave were taking their surroundings into consideration.”

Drawing of life-size human figure in 19th Unnamed Cave, Alabama
Drawing of life-size human figure in 19th Unnamed Cave, Alabama Photograph by S. Alvarez / Illustration by J. Simek
Drawing of life-size human figure in 19th Unnamed Cave, Alabama
Drawing of life-size human figure in 19th Unnamed Cave, Alabama Photograph by S. Alvarez / Illustration by J. Simek