An underground fire in Australia has been burning for approximately 6,000 years, making it the world's oldest known coal fire.
Australia's 6,000-Year-Old Underground Fire
Deep beneath a hill in New South Wales, Australia, a fire has been burning continuously for approximately 6,000 years. That's older than the Egyptian pyramids, older than Stonehenge—this underground inferno has outlasted entire civilizations.
The site, known as Burning Mountain or Mount Wingen, is located about 224 kilometers north of Sydney. To early explorers, the smoking hillside seemed like evidence of volcanic activity. It wasn't until 1829 that geologist Reverend C.P.N. Wilton identified the true culprit: a burning coal seam running underground through layers of sandstone.
How It Started (Probably)
Scientists believe the fire ignited around 4,000 BCE when lightning struck a coal seam exposed at the Earth's surface. Once the coal caught fire, it began a slow, relentless journey underground. Some theories suggest a bushfire could have started it, or even spontaneous combustion from chemical reactions in the coal itself. The exact cause remains a mystery lost to prehistory.
A Fire That Moves
This isn't a stationary blaze. The coal fire creeps southward at about one meter per year, currently burning approximately 30 meters (100 feet) underground. Over millennia, it has carved a burning path stretching 6.5 kilometers.
Scientists calculate the fire's age by measuring this scorched trail and estimating how fast it travels. Some researchers suggest it could be even older—potentially hundreds of thousands of years old, though 6,000 years is the most widely accepted estimate.
What It Looks and Feels Like
Visitors to Burning Mountain Nature Reserve can experience this ancient phenomenon firsthand. The telltale signs include:
- White sulfuric smoke rising from cracks in the ground
- Soil that's warm—even hot—to the touch
- Rocks discolored yellow and red from the heat
- A distinctive sulfuric smell hanging in the air
The fire doesn't produce flames you can see. Instead, it smolders underground, slowly consuming the coal seam and heating everything above it.
The World's Oldest Fire
Burning Mountain holds the Guinness World Record for the longest-burning fire. While other coal seam fires exist around the world—some caused by mining accidents or natural ignition—none have the documented longevity of Mount Wingen's subterranean blaze.
The fire will continue burning until it exhausts the coal seam, which could take thousands more years. It's a reminder that some natural processes operate on timescales that dwarf human history—a flame that's been burning since the Stone Age, and will likely still be smoldering long after we're gone.