The burning coal seam at Brennender Berg in Saarland, Germany ignited in 1688 and has been burning ever since. No one is sure how the fire started (probably spontaneous combustion), but legend has it a shepherd lit a fire near a tree stump, which went through the roots and into the coal seam.
What is known for sure is that the famous poet Johann Wolfgang von Goethe visited Brennender Berg in 1770 and wrote about his travels and encounter with the burning mountain: “Dense steam arose from the crevices and we could feel the hot ground even through the thick soles of our shoes.”
There is even a plaque memorializing his visit at the site. Though the intensity of the coal fire has lessened since the 1800s, visitors can still see smoke rising from the rocks and even feel hot steam coming from cracks and openings.
It is said that before the fire intensity lessened, schoolchildren were taken on field trips to see the burning mountain and would steam eggs at these openings.