Wang Mantang starts and ends his days by the fire. The thing is, the fire never stops burning.

Seven or eight flames constantly lick up from the four-meter square patch in a village in Chongqing's Changshou district in southwest China. Regardless of weather, the spot kindles year-round. Locals flock to the location in a twice-a-day ritual to boil water, which takes only about five minutes.

"Firewood used to be expensive in the past and sometimes we had to go to the western mountainous areas to carry back bundles of firewood," Wang told CCTV+. "But it was more convenient here. We came here with our cooking pots and queued to boil sweet potatoes and pigweed."

Underground fires spring up across the world, from warmer climates like China to icier ones like Siberia. The U.S. is even home to one of these incessant sparks in Centralia, Pa., which started burning some 50 years ago. They're ignited by lightning strikes, human ignitions, mining, or spontaneous combustion, and once they're started, these fires can burn for decades.

"Normally they are similar, and the causes of fire could be different," says Anupma Prakash, a geophysics professor at the University of Alaska at Fairbanks. "Once the fire starts, the problem is very similar globally."

Coal is normally the culprit for underground fires in China, and the coal-producing giant has 62 of these blazes scattered across the north. The fiery patch in Chongqing started 59 years ago when an oil exploration team drilled a natural gas well at the site. The workers left the well largely unexplored, and it has been emitting excess gas and fueling the flames ever since.

Putting the Flames to Work

The village people of Chongqing have found a way to use the flames to their advantage by manipulating them for cooking. Other communities have channeled subterranean burns into creative uses, like Australia's tourist-attracting Burning Mountains. But overall, Prakash says, the negatives of these fires outweigh the positives.

"When fires are in the underground, what they do is they literally eat up the coal," she says. Compacted by pressure, the land can collapse into sinkholes, sucking in buildings and more oxygen to fuel the flames. This can lead to uneven, "rugged" landscapes and potholes.

With hollow ground, cracks can form on the surface. Where there's fire, there's smoke, so a toxic mixture of carbon monoxide, sulfur dioxide, and coal dust billows up from the earth, polluting the air. Not only does this worsen climate change by adding to greenhouse gases in the atmosphere, but it's plain old bad for your health.

"The smoke is all around in the landscape," Prakash says, adding that the smell of eggy sulfur is ubiquitous. "That's just really unhealthy. Imagine inhaling that 24/7, year-round."

The problems are also economic. China's coal is pure anthracite, making it the best-quality coal in the world. Underground fires eat up the fuel, which could otherwise be used for more deliberate—and cost-efficient—purposes.

Putting Them Out

It is possible, Prakash says, to staunch the flames. All fires need three ingredients—fuel, oxygen, and heat. If you cut off one of these, you kill the fire. Some communities deal with underground fires by dousing them with water-and-slurry mixtures or other natural resources. Others use swelling clay, which expands to cut off oxygen and choke out the flames. Liquid nitrogen has also been used to extinguish underground fires.

How long will the fire in this Chongqing village burn? It's hard to tell, but Wang and others may be returning to the flames for years to come.