Scattered across a vast hilltop in West Java, Indonesia, is one of the largest megalithic archaeological sites in Southeast Asia: Gunung Padang. Though the site was first discovered by Dutch explorers back in 1914, a full archaeological examination of the site only began more recently.

Now, Indonesian researchers excavating there have made an extraordinary claim. They have unearthed evidence that the site represents the remnants of a pyramid-like structure that could be anywhere from 9,500 to 28,000 years old. If confirmed, that would make Gunung Padang the oldest pyramid-like structure ever found, by a long shot.

The findings are detailed in a new paper, though have yet to be peer reviewed.

The paper claims that the structures at Gunung Padang are organized as a layered series of ancient structures that were built successively over time. Radiocarbon dating puts the top layer, which consists of rock columns, walls, and paths, at "only" about 3,500 years old. But the foundation of the structure is clearly ancient, even considering that the range of possible dates for it, as outlined in the findings, is wide.

"Our studies proves that the structure does not cover just the top but also wrap around the slopes covering about 15 hectares area at least," the authors write in the paper's abstract. "The structures are not only superficial but rooted into greater depth."

Archaeologists aren't sure what this ancient structure was built for. The best-guess is that it was a religious temple of some kind, but that's still just a guess.

Of course, the fact that the paper remains non-peer reviewed has also fueled a fair amount of skepticism over the findings. In contention are new claims about the more ancient layers of the structure, which previous research had merely labeled as natural rock formations. These structures are also important for the "pyramid" claim, as they make up the foundation of the site.

However the evidence ends up falling, the site is a reminder that prehistoric societies were capable of much more than we've probably given them credit for. It should be an adventure to see what secrets further research might reveal.

Possible pyramid has been unearthed in Indonesia that could be 28,000 years old
Researchers have unearthed evidence that Gunung Padan represents the remnants of a pyramid-like structure that could be anywhere from 9,500 to 28,000 years old.