There used to be a place called Centralia, Pennsylvania. The town incorporated in the 1860s and once had several thousand residents, largely coal workers. But the story of its demise begins a century later in 1962. That year, a trash burning fire was lit in the pit of the old abandoned coal mine outside of town. The fire moved down the mineshaft and ignited a vein of coal. It is still burning. For more than twenty years, people tried to extinguish the underground fire, but no matter what they did, it returned. There was little government action, and people had to abandon their homes as toxic gases engulfed the area and sinkholes developed. In 1983, engineers studying the fire concluded that it could burn for ________________ and could spread over nearly 4,000 acres.