Since May 1962, an underground coal fire has been burning continuously beneath the town of Centralia, Pennsylvania. The fire began when a landfill fire, set in an old open pit, spread into a coal seam known as the Buck Mountain vein. This vein is part of a vast network of abandoned mines beneath the area, and once the fire reached it, it found a path through the tunnels and galleries left behind by past mining operations. Despite numerous efforts—such as digging trenches, injecting fire-retardant materials, and excavating areas—nothing has been able to stop the fire from spreading. Over time, the fire has moved deeper underground and over a larger area, now burning at a depth of about 90 meters and covering roughly 13 kilometers. The fire’s slow but persistent advance forced nearly all of Centralia’s 1,000 residents to leave between the 1980s and 2002. The town’s postal code was eventually abolished, and its post office closed. The fire is estimated to have enough coal to burn for up to 250 years, though this figure remains debated. In 1979, a gas station attendant discovered that the temperature of underground fuel tanks had risen dramatically—172 degrees Fahrenheit, far above normal—indicating the fire’s growing reach. This, combined with a child nearly falling into a sinkhole and rising carbon monoxide levels, led to federal funding for residents to relocate. Most accepted compensation and left, leaving behind homes that were later demolished. Despite these efforts, the fire continues to advance at a rate of a few meters per year. Pennsylvania authorities still monitor the site with monthly visual checks and annual temperature readings in boreholes. Fumaroles, or vents releasing hot gases, can still be seen between trees in the area. While the fire is not unique to Centralia—thousands of underground coal fires burn globally—it has become a symbol of the long-term environmental and human impact of such events. In other parts of the world, similar fires have significant environmental consequences. In China, the world’s largest coal producer, these fires consume or render inaccessible between 10 and 200 million tons of coal annually. Indonesia and India also face large-scale underground coal fires, with India’s Jharia basin burning since 1916. Collectively, these fires contribute to up to 3% of global CO2 emissions and release 40 tons of mercury into the atmosphere each year. In Centralia, the fire has even created a unique natural feature: the Big Mine Run Geyser, which erupts when heavy rains meet the pressure from the underground fire. While the geyser is now maintained to prevent flooding, the fire itself continues its slow, unimpeded advance beneath a road that no longer sees any traffic.