When explorers came across Burning Mountain in the 18th century, they mistook it for a volcano. However, it turned out they had stumbled on something much stranger. Found in Australia’s New South Wales, this is the site of the world’s oldest known coal fire that hasn't gone out for thousands of years.
Most scientists believe the fire has been burning for at least 6,000 years, although some contend it’s much older.
It’s located around 30 meters (98 feet) underground beneath Mount Wingen. The word Wingen, by no coincidence, means “fire” in the aboriginal language of the local Wonaruah people. Since it is underground, it’s not possible to see the fire or even discern its size, but smoke rising from the mountain is evidence of its presence.
"No one knows the size of the fire under Burning Mountain, you can only infer it," Guillermo Rein, a professor of fire science at Imperial College London in the UK, told ScienceAlert in 2022.
"It's likely a ball of around 5 to 10 meters [16 to 32 feet] in diameter, reaching temperatures of 1,000 degrees Celsius [1,832 Fahrenheit]," he explained
It’s fuelled by the stacks of coal lying beneath the mountain. Just like a lump of coal turning white in a fireplace, the flameless fire slowly creeps through the coal at around 1 meter (over 3 feet) per year.
The age estimates are worked out by measuring the path of the fire, which stretches for around 6.5 kilometers (4 miles), and the rate at which it burns. The truth is, however, no one knows when it started.
It’s not certain how the fire started either, but it almost certainly wasn’t humans. A lightning strike or a ferocious brush fire are considered the best explanations.
Writing in a blog post that details his visit to Burning Mountain, Professor Rein explains that the heat pumped out from the coal fire has created a 50-meter (164-foot) area around the hilltop that’s devoid of any vegetation.
He notes that similar underground coal fires have been found elsewhere in the world, most notably in China, India, and the US. For instance, the Centralia mine fire in Pennsylvania was ignited by accident in 1962 at a labyrinth of abandoned coal mines. Despite several attempts to extinguish it, it’s still burning to this day and is expected to continue blazing for another 250 years.
You can catch a glimpse of Burning Mountain if you visit the Burning Mountain Nature Reserve, less than a four-hour drive from Sydney. Make sure you don’t light a cigarette here, though – the nature reserve’s website makes it very clear that this is a no-smoking area.