There are places on Earth that are a little creepy, places that feel a little haunted and places that are downright hellish. The Darvaza gas crater, nicknamed by locals "The Door to Hell," or "The Gates of Hell," definitely falls into the latter category—and its sinister burning flames are just the half of it. Located in the Karakum Desert of central Turkmenistan (a little over 150 miles from the country's capital) the pit attracts hundreds of tourists each year. It also attracts nearby desert wildlife—reportedly, from time to time local spiders are seen plunging into the pit by the thousands, lured to their deaths by the glowing flames. 
 
 So how did this fiery inferno end up in the middle of a desert in Turkmenistan? In 1971, when the republic was still part of the Soviet Union, a group of Soviet geologists went to the Karakum in search of oil fields. They found what they thought to be a substantial oil field and began drilling. Unfortunately for the scientists, they were drilling on top of a cavernous pocket of natural gas which couldn't support the weight of their equipment. The site collapsed, taking their equipment along with it—and the event triggered the crumbly sedimentary rock of the desert to collapse in other places too, creating a domino-effect that resulted in several open craters by the time all was said and done. 
 
 The largest of these craters measures about 230-feet across and 65-feet deep. Reportedly, no one was injured in the collapse, but the scientists soon had another problem on their hands: the natural gas escaping from the crater. Natural gas is composed mostly of methane, which, though not toxic, does displace oxygen, making it difficult to breathe. This wasn't so much an issue for the scientists, but for the animals that call the Karakum Desert home—shortly after the collapse, animals roaming the area began to die. The escaping methane also posed dangers due to its flammability—there needs to be just five percent methane in the air for an explosion to potentially take place. So the scientists decided to light the crater on fire, hoping that all the dangerous natural gas would burn away in a few weeks' time. 
 
 It's not as outlandish as it sounds—in oil and natural gas drilling operations, this happens all the time to natural gas that can't be captured. Unlike oil, which can be stored in tanks indefinitely after drilling, natural gas needs to be immediately processed—if there's an excess of natural gas that can't be piped to a processing facility, drillers often burn the natural gas to get rid of it. It's a process called "flaring," and it wastes almost a million dollars of worth of natural gas each day in North Dakota alone. 
 
 But unlike drillers in North Dakota or elsewhere, the scientists in Turkmenistan weren't dealing with a measured amount of natural gas—scientists still don't know just how much natural gas is feeding the burning crater—so what was supposed to be a few-week burn has turned into almost a half-century-long desert bonfire. 
 
 After visiting the crater in 2010, Turkmenistan's president Kurbanguly Berdymukhamedov, worried that the fire would threaten the country's ability to develop nearby gas fields, ordered local authorities to come up with a plan for filling the crater in. No action has been taken, however, and the crater continues to burn, attracting unsuspecting wildlife and international tourists. 
 
 To visit the Darvaza gas crater, it's best to go at night, when the fire can be seen from miles away. The crater is located about 161 miles (about a 4 hour drive) from the Turkmen capital Ashgabat. Tours can be booked through agents in Ashgabat. Alternatively, some companies offer more structured tours of the surrounding area, with the Darvaza crater included (such as this tour, by The Geographical Society of New South Wales). ||||| Scientists were baffled last July when they discovered three giant holes in the ground in the Yamal Peninsula in northern Siberia. 
 
 Now, with the help of satellite imagery, researchers have located four additional craters--and they believe there may be dozens more in the region. That has them calling for an urgent investigation to protect residents living in the area. 
 
 "I am sure that there are more craters on Yamal, we just need to search for them... I suppose there could be 20 to 30 craters more," Prof. Vasily Bogoyavlensky, a corresponding member of the Russian Academy of Sciences and deputy director of the Moscow-based Oil and Gas Research Institute, told The Siberian Times. "It is important not to scare people, but to understand that it is a very serious problem and we must research this." 
 
 Researchers ventured deep inside one of the holes last November, collecting data in an effort to learn why the holes formed. The leading theory is that the holes were created by gas explosions triggered by underground heat or by rising air temperatures associated with climate change, the Siberian Times reported last December. 
 
 Since scientists can't predict when or where gas explosions will occur, it's dangerous to study them, according to Bogoyavlensky. But he said his team is planning to launch a new expedition, and to put stations in the area to detect earthquakes that might strike when the craters open up. 
 
 "We need to answer now the basic questions: what areas and under what conditions are the most dangerous?" he told the Siberian Times. "These questions are important for safe operation of the northern cities and infrastructure of oil and gas complexes." 
 
 Experts in the U.S. echoed that sentiment. 
 
 Dr. Carolyn Ruppel, a research geophysicist at the Woods Hole Field Center in Massachusetts and chief of the U.S. Geological Survey's Gas Hydrates Project, told The Huffington Post in an email that she was not surprised that new holes had been found. 
 
 Ruppel, who is not involved in the Siberian research effort, called for more research on the holes. 
 
 "The processes that are causing them to form likely occur over a wide area of the continuous permafrost in this part of Siberia," she said in the email. "Scientists should definitely conduct more research on these features to determine the processes that cause their formation, how they evolve with time, and whether it is possible to predict where new ones will occur." 
 
 See below for photos from the November's expedition into one of the craters. 
 
 PHOTO GALLERY BEFORE YOU GO Experts Explore Mysterious Siberian Crater PHOTO GALLERY Experts Explore Mysterious Siberian Crater
– A fiery pit has been burning in the middle of a Turkmenistan desert for more than four decades, and little has been done to get rid of it. The Darvaza gas crater, nicknamed the "Gates of Hell" or the "Door to Hell," has been on fire since 1971, when scientists were looking for oil fields in the Karakum Desert, then part of the Soviet Union. The spot where they began drilling turned out to be a haven for natural gas—and the site collapsed under the weight of the drilling gear, Smithsonian magazine reports. Several craters were formed, the biggest of which is 230 feet wide and 65 feet deep, and it was full of methane gas that began killing local animals. So scientists decided to burn the gas away, a common practice when unwanted natural gas is sticking around. They thought it would be gone in a few weeks; now, more than 40 years later, it's still burning, and experts aren't sure how much gas remains. Officials have called for action to stop the flames, to no avail, the Smithsonian notes. The spot, which is visible from miles away, has become a tourist attraction, oilprice.com reports. Visitors can stay in tents and view the site—as well as "huge and largely harmless spiders" that hang out nearby.