An Austrian winemaker made an unexpected discovery while renovating his wine cellar — and it wasn’t an old bottle of Blaufränkisch. According to a Wednesday press release from the Austrian Academy of Sciences (OeAW), bones accidentally uncovered by Andreas Pernerstorfer have been confirmed as belonging to at least three different Stone Age mammoths.

Pernerstorfer was deep in his wine cellar, located in the village of Gobelsburg, when he discovered the treasure trove of fossils. The winemaker first thought the bones were old pieces of wood, but then recalled a story he’d heard from his grandfather, who had found mammoth molars when he extended the wine cellar in the ‘60s, a researcher told CNN. Pernerstorfer reported the findings to the Federal Monuments Office which referred him to the OeAW, who later arrived to inspect the scene.

OeAW researchers are still recovering the bones and have described it as an “archaeological sensation,” citing it as the most significant finding of its kind in over 100 years.

“Such a dense bone layer of mammoths is rare,” Hannah Parow-Souchon, a researcher leading the excavation, said in the release. “It’s the first time we’ve been able to investigate something like this in Austria using modern methods.” The last time such a discovery was made in Austria was 150 years ago in the same district of Krems.

Upon further inspection, researchers were able to uncover several more layers of mammoth bones. Stone artifacts and charcoal found at the site indicate that the bones are between 30,000 and 40,000 years old. After the fossils are further examined, they will be handed over to the Natural History Museum in Vienna.