SciShow host Hank Green explains the science behind the coal fire that has been burning under Centralia, Pennsylvania consistently since 1962. In spite of that length, however, the fire is by no means one of a kind. There are currently around 150 coal fires burning in the United States alone.
Scientists estimate that there’s enough coal beneath Centralia to fuel the fire for yet another 250 years. And yet, that’s nothing compared to Australia’s aptly named Burning Mountain, under which a 6,000-year-old fire continues to burn through a seam of coal in the Earth.