I did a fair bit of Australian geography in school. How was it that no one mentioned that Australia has an underground fire that has been burning since....who knows! It was certainly already burning before European settlement. Burning Mountain Nature Reserve is located on the New England Highway, about 300 km north of Sydney. A two-metre thick coal seam is continually on fire about 20 -30 metres under the surface of the ground, releasing heat and toxic fumes from outlet at ground level. That's amazing. And I can't believe no one ever mentioned it. Or maybe I just wasn't listening at the time. You can read more information here.