On the outskirts of Melbourne, a set of large concentric earth rings that had long baffled researchers are now understood to be the work of Indigenous Australians.

A new study on the site in Sunbury, Victoria, carried out in partnership with the Wurundjeri Woi‑wurrung people, concludes that the rings were constructed between around five hundred and fourteen hundred years ago.

The formations, located on land traditionally belonging to the Wurundjeri Woi-wurrung, measure up to hundreds of metres in diameter and were once assumed to be natural or unexplained anomalies.

Excavation and artefact analysis at one structure known as ‘Ring G’ reveal that the ground was scraped, rocks were layered into patterns and stone tools were used inside the ring area.

Some wear marks and residue suggest that these tools were used for tasks such as feather‐adornment crafting or possibly scarification linked to ceremonial practice.

Researchers say the earth rings likely served as gathering places, ceremonial enclosures or initiation sites for the Wurundjeri Woi-wurrung and possibly neighbouring clans.

The rings lie on the border of traditional clan territories and appear to align with travel and gathering routes in the biik wurrdha (Jacksons Creek) landscape, underscoring their cultural importance.

Although similar earth-ring structures have been documented in New South Wales and Queensland, the Sunbury formations are among the few in Victoria whose origin has now been detailed.

It is estimated that Australia once contained hundreds of these rings, yet fewer than one hundred remain today, many lost to land development and colonisation.

The findings deepen understanding of Indigenous land use, social organisation and landscape modification in southeastern Australia over the last millennium.

They also highlight the ongoing custodianship of the Wurundjeri Woi-wurrung people, who led parts of the research and continue to manage cultural landscape values at the site.

Preservation of these earth rings is now a priority for local authorities and Indigenous groups, as they remain vulnerable to development, erosion and other risks.

Documentation of their construction and cultural role strengthens the case for their protection as integral features of Australia’s living heritage.