The panel in 2024 (left) and a software-enhanced version of the photo (right). Credit: Nash et al. 2026/Quaternary

This cluster of rust-red streaks inside a cave on the Welsh coast survived since the end of the Ice Age—only for modern experts to dismiss them as natural mineral stains. Skeptics wrote off the parallel lines as a geological fluke, and the site faded from scientific memory for nearly a century.

Now, an international team of researchers has proved the skeptics wrong. Using advanced radiometric dating on the mineral crust covering the pigment, scientists determined that an ancient human deliberately painted the 11 lines roughly 17,000 years ago. That puts the Bacon Hole panel, as it’s called, more than 3,000 years ahead of anything else ever found in Britain.

Acknowledging a Masterpiece

British geologist and paleontologist William Sollas and French priest and pioneering archaeologist Henri Breuil originally discovered the markings in 1912. They found the panel of red lines deep inside Bacon Hole, a cave located on the Gower Peninsula in southwest Wales.

By 1928, skeptics successfully argued the markings were a natural phenomenon. The scientific community forgot the exact location of the panel until an international team of researchers finally relocated it in 2022.

To uncover the truth, scientists analyzed the calcite crust covering the pigment using uranium-thorium dating. This radiometric technique measures radioactive decay to determine the age of rock formations. The tests confirmed the paintings are between 15,700 to 18,300 years old. Before this finding, the oldest known British rock art was a 14,500-year-old reindeer engraving discovered in a nearby cave.

“It was never considered to be rock art after 1928, and also it could never be dated, because in those days they didn’t have the scientific means that we have today,” lead author George Nash told The Guardian. “I was taken aback that we were able to date it and analyze the pigments.”

The mouth of Bacon Hole cave. Credit: Quaternary

The Meaning Behind the Marks

The ancient artists created the equidistant lines using a deliberate mixture of clay and hematite, an iron oxide compound. Digital color enhancement revealed finger dots and pigment splashes, indicating the creators blew or spat the paint onto the cave wall.

Why did ancient humans leave these deliberate marks?

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The physical placement of the panel deep inside a dark chamber points toward a spiritual or ceremonial purpose.

“The darkness itself may have been an essential part of the ritual experience,” Nash told Live Science. “Deep cave chambers are acoustically unusual, visually disorienting, and separated from the everyday world. Entering such spaces could have created a sense of transition to a different realm.”

When humans painted these lines, the surrounding valley was a treeless plain where mammoths and bison roamed. For thousands of years, generations of visitors kept returning to the cave, leaving behind a trail of artifacts that included Roman bone pins, medieval cooking pots, and 19th-century graffiti.

Today, a steel grille seals the entrance to the side chamber, protecting both the fragile pigment and the bats that roost there each winter. The barrier marks the cave’s latest chapter, turning a space once altered by Ice Age hunters into a permanent sanctuary. Millennia after an unknown artist left those first red marks, Bacon Hole stands as a physical anchor for the deepest roots of human expression in the British Isles.

The study was published in the journal Quaternary.