Editor’s note 3/20/24: The publisher Wiley has issued a retraction of this paper after concerns raised by independent researchers, concluding the study contains a major error in its methods and thus conclusion.

If you thought the ancient inhabitants of Egypt or South America were the first to build pyramids then you may need to think again, because new research indicates that the earliest human-made conical monument may have been constructed in Indonesia as far back as 25,000 years ago. Known as Gunung Padang, the site had previously been assumed a natural hill, but now researchers claim extensive fieldwork has revealed that the entire structure was in fact built by human hands over the course of several millennia.

Located in Cianjur District, West Java Province, Gunung Padang is a megalithic complex that sits atop an eye-catching hill. It was only in 2018 that archaeologists first theorized that the entire mound may actually have been artificial, and that Gunung Padang - which means “Mountain of Enlightenment” - encompasses much more than the visible stone structures sitting on its surface.

This startling claim was made by a multidisciplinary team of researchers who had spent three years surveying the site between 2011 and 2014. And while many experts remain unconvinced, the researchers have now published a detailed account of their investigations, providing evidence to support the idea of Gunung Padang as the world’s oldest pyramid.

“Radiocarbon dating of organic soils from the structures uncovered multiple construction stages dating back thousands of years BCE, with the initial phase dating to the Palaeolithic era,” write the authors. “This study strongly suggests that Gunung Padang is not a natural hill but a pyramid-like construction,” they continue.

Using a variety of techniques including electrical resistivity tomography (ERT), ground-penetrating radar (GPR), and seismic tomography (ST), the researchers were able to build a picture of the hill’s internal features as well as the chronology of its construction. Core drillings at seven different points revealed that the pyramid was built in four distinct stages over thousands of years.

Spanning 20 to 30 meters (65 to 98 feet) in height, the structure began with the creation of what the authors call Unit 4. Buried deep within the hill, this initial phase “likely originated as a natural lava hill” that was “meticulously sculpted” into its current form some time between 25,000 and 14,000 years ago. 

Unit 3 - which consists of columnar rocks “arranged like bricks in a building” - was then built between 7900 and 6100 BCE. “Approximately a millennium later, between 6000 and 5500 BCE, a subsequent builder arrived at Gunung Padang and constructed Unit 2,” write the authors, who add that “the final builder arrived between 2000 and 1100 BCE, constructing Unit 1.”

Intriguingly, the team also found evidence of “hidden cavities or chambers within the site”, though these will need to be explored in greater detail during future field surveys. Even more bewildering is the fact that the site appears to have been deliberately buried on numerous occasions, “possibly to conceal its true identity for preservation purposes”.

Noting the “remarkable masonry capabilities” of the palaeolithic instigators of Gunung Padang, the researchers say their findings challenge the assumption that sophisticated building techniques were only developed with the advent of agriculture some 11,000 years ago. 

The study is published in the journal Archaeological Prospection.