The Freemasons Yearly Meeting
Some conspirators claim that the cave is actually a door to tell. Others think it connects to an underground tunnel system that connects all Mason-used locations. Of course, there's also the group who believe that the tunnel holds satanic worship services and sacrifices in the cave.
Centralia, Pennsylvania
In 1962, the town of Centralia lit a landfill on fire in hopes of getting rid of some trash. The fire spread to the underground coal mines that were responsible for the town's economy. The fires made the town so unsafe that the state forced evictions to keep them safe. Right now, seven people remain in the town that used to house hundreds.